 Good morning everyone, welcome to the discussion on environmental monitoring for management of Legionella in water systems. In 2017, a committee was put together by the National Academy of Sciences, Engineering and Medicine, Water Science and Technology Board to address this important topic. I was honored to chair this distinguished committee. I'm Joan Rose from Michigan State University. Our members were Nicholas Ashbolt, Ruth Berkelman, Ruth Gutilius, Charles Haas, Mark Lechevalier, John Lutzon, Steve Pergam, Michelle Pravol, Amy Prudin, Michelle Swanson, Paul Vanderwillen and Nanji Weeks. We were directed by Laura Ellers, our senior staff officer. As you can see, this distinguished group was made up of environmental engineers, microbiologists, medical professionals and public health specialists. As a result of this committee work and in the end of 2019 we produced a report management of Legionella in water systems and this is available for your download. It includes five chapters. Chapter one was just an introduction to the disease and what we know so far about Legionella. We've got a chapter on diagnosis and ecology, but we are going to be focusing today on the quantification of Legionella in water system. We had a chapter on prevention and control strategies and of course measuring both the disease and the bacteria in water systems is integral to looking at prevention and control in water systems. And finally, we evaluated regulations and guidelines on Legionella control. Chapter three focused in as I said on quantification of Legionella and Legionnaires disease. The committee estimated that there were actually anywhere from between 52,000 and 70,000 cases of Legionnaires disease in the United States each year. And you can see that the disease was going up both in Europe and US, which was part of the emphasis for this report. Environmental monitoring was a key part of this chapter. And the committee looked at hundreds of papers from all over the world on monitoring of Legionella in water system and compiled that data. And finally, the committee took on a quantitative microbial risk assessment for Legionella pneumophila. Methods are evolving of course for quantification of Legionella. The purpose can be for diagnosis outbreak investigation routine monitoring mitigation assessment and research. We have many tools of course there's a standard culture method which has evolved over many years, but we have new culture methods available to us and quantitative molecular tools. This can distinguish between Legionella species, Legionella pneumophila, serogroup 1 and other species like anacea. Most of the methods are quantifiable that is we can get concentrations. And of course the pros and cons the culture method takes a long time it can underestimate the levels there because of viable non-cultural cells. And finally PCR methods, while they can detect many different species, detect both live and dead. Interestingly enough the committee was able to look at concentrations that were monitored in water systems, a variety of water systems during routine sampling and during outbreaks. And there was a demarcation, a level in which you could demarc or distinguish between concentrations found in non outbreak situations and concentrations found in outbreaks. This 50,000 colony forming units per liter is a level that weren't serious concern in the committee's view is considered an action level. This is where immediate remediation should take place. Obviously no one wants to be near a concentration of Legionella in which there could possibly be an outbreak. The committee also looked at QMRA. I looked at the risk of infection at 10 to the minus four in devices and fixtures, as well as a dolly the disability adjusted life years, which takes into the account the impact of the morbidity mortality. And you can see that these are some of the numbers as low as 1410 colony forming units for conventional shower at 10 to the minus four and for the dolly a conventional shower at 14 at one in a million risk. In chapter five, we reviewed the federal laws and regulations pertinent to Legionella, the state and local regulations or guidelines, and what were enforceable policies. Most of these are guidance documents. And we also evaluated where the rules and policies were going in other countries. And finally, there were recommendations on monitoring and steps forward. Our recommendations included the expanding the centers for Medicare and Medicaid services memo to require monitoring for Legionella and environmental water samples for all hospitals, register and monitor cooling towers, require water management plans in all public buildings, including hotels, businesses, schools, departments, government buildings, and required temperature of 60 degrees at hot water heaters and 55 degrees at distal points. And finally require minimal disinfectant residuals and monitor for Legionella throughout the public water system. Today's program has a number of our committee minimers presenting Amy Prudin will present three purposes of Legionella monitoring. We will then held a panel to discuss. How do we look at these action levels and thresholds. And finally, we will after a break, have two presentations on where and when monitoring should occur. Michelle provost, provost will speak on buildings and cooling towers, and Mark Lechevalier will talk about utilities and distribution systems. We will finally have questions from the audience. Thank you so much. And we look forward to hearing from all of you. Now turn that over to Amy. Hey, here we go. Well, it's good to be here together as a committee again and have this opportunity to consider next steps for the NASCM Legionella report. So today we're focusing on recommendations regarding monitoring of Legionella and water systems and what that might look like in practice. So my aim here is to provide kind of a big picture overview of the purpose of Legionella monitoring and implications of the methods selected. So, I'm starting here with what has now become an infamous exemplar in Flint, Michigan, and how district disruptions in the municipal water system and operation can and should be a red flag for Legionella. So there's an intimate connection between the water chemistry variables and the potential for disease outbreak. In the report we identify four main purposes for testing Legionella in the water. And the first is outbreak response. So you have the unfortunate situation that an outbreak is already underway, and you need to find the source and mitigate the spread. Similarly, you want to prevent the outbreak in the first place. And here Legionella monitoring can help to identify red flags and where there's vulnerability for transmission. And the third would be that you've identified locations in the water system from the outbreak response or routine monitoring that are concerned. And now you're applying some sort of mitigation such as disinfectant or elevated temperature, and you need to show that this is actually causing Legionella numbers to go down. And the fourth is a general category I would call research. So here you might see a wider variety of methods and approaches applied with the aim of advancing the science and understanding how Legionella proliferates and how it can be controlled. So key motivation for action here. And this was emphasized in the report is that the Safe Drinking Water Act does not provide protection from Legionella. At best municipal water utilities are legally required to provide a target disinfectant residual to the property line. And there's no requirement for Legionella monitoring. Also the target disinfectant residuals were not really selected with Legionella in mind. And a key barrier is that, except for the lead and copper rule, regulations stop at the property line. And it's within the premise plumbing where conditions are especially conducive to Legionella growth. You have high surface area to volume ratio, which encourages biofilm formation, warmer temperature within the growth range of Legionella and higher water age and reactive pipe materials which lead to disinfectant loss. I also mentioned here cooling towers, which efficiently serve their purpose for indoor temperature control and large buildings, but also have to be watched carefully because they inherently operate within the ideal Legionella growth temperature, and they produce aerosols that can effectively deliver Legionella to the lungs and cause infection. So here appropriate disinfection and cleaning is essential. So if we're going to monitor Legionella, what to monitor? And it's not quite that simple. For one, there's 61 known species of Legionella and a handful are known to cause disease. But Legionella pneumophila is by far the most notorious and is the most widely recovered from patients associated with risk and best characterized. Still, even within Legionella pneumophila, there are 14 serogroups and the clinical urine antigen test only captures serogroup one, while environmental testing can in theory capture all of the serogroups. And there's also numerous sequence types, which can be determined by whole genome sequencing or sequencing of seven specific alleles, but this is usually only done in the case of an outbreak investigation. So in a perfect world, what would we want our ideal method attributes to be? Here's the wish list. We'd want something that's specific, sensitive, quantitative, fast, high throughput, discriminant, economical, easy to use, in situ, and importantly, indicative of risk. That's that it's representative of an infectious transmissible target that is informative to risk assessment. For example, we know much more about L pneumophila when it comes to disease transmission. So many have suggested that this should be the focus of monitoring. So what do we have in terms of methods? Culture has long been the gold standard with appropriate confirmation testing. It is specific and it's sensitive. If you do a good job guessing the dilution and effectively get rid of background organisms, which is really hard with cooling tower water, then it's quantitative. Most importantly, it's the only approach that's going to exclusively be discriminant and report on live organisms, though by definition it's going to miss viable but non-culturable or VVNC. And the main drawback to culture is that it is slow at a minimum it's going to take three to seven days for results, which can be problematic and urgent situations. So suitable applications absolutely in an outbreak response, it's going to be the only way to identify the source strain by comparing to clinical strains. It's also the only way to verify for sure that any mitigation is actually killing the Legionella. In recent years QPCR has been emerging as an alternative DNA based technique that can be appropriate in some situations. So QPCR is highly specific and you can zoom in on your target of interest, be it Mophila, serogroup one, whatever it's very fast, and if all goes well you'll have results in less than a day. QPCR has similar sensitivity to culture, very wide quantitative range, and it's ideal if high throughput is the goal. But it's Achilles heel is that it can't directly distinguish living Legionella from dead or VVNC Legionella. A suitable application therefore would really be as a rapid screen for culturing or for really broad monitoring of multiple sites to be able to identify any anomalies. And although it can't directly verify Legionella is killed, you can couple it with culture and show that a mitigation is working and numbers of Legionella are going down in the long term. In terms of culture methods, the gold standard is currently the ISO method and BYCE medium. Again, this is going to take three to seven days for growth. Plus you have to do confirmation, which will be another three to seven days by culture but there's quicker methods now like Maldi and PCR. The culture method tends to be biased towards pneumophila, but you're going to pick up other Legionella species as well. And as I mentioned, a key point is that isolates can be obtained for outbreak investigation. There's emerging commercial methods like Legionella and they're starting to gain substantial ground. The intention here is a test that's very user friendly, you don't have to send to an outside lab and it's high throughput. A key distinction with Legionella though by design as it captures only L pneumophila, which in theory is more informative target for risk. So we're going to go under way with this method. For example, looking at what grows in the wells with different water types. PCR methods are also gaining ground. For example, the report highlights how it was used for rapid screening of cooling towers in New York following the Bronx outbreaks, which were then followed up with culture. It's very advantageous because it has a very wide range of quantitation. There's this droplet digital QPCR, which is a new variant that's improving sensitivity even further. And PCR and QPCR are also advantageous because of their specificity. So you can choose exactly which target you're interested in, whether it's Legionella species at the genus level or L pneumophila or even Sarah group one there's primers available. I also wanted to point out that the Water Research Foundation has been highly active on this front, and they have an ongoing project looking at optimizing QPCR monitoring for Legionella and premise plumbing. And there's also a new infield QPCR unit coming online, which are intended to make the method even more rapid and user friendly. Okay, so let's say we've chosen our method and our target. As Joan talked about what's our reasonable action level. And so this is a from the report, you know, ideally, this target should be risk based, but that's not always so easy to discern from building to building. One thing the report laid out was okay what what were the concentrations of Legionella reported in the literature associated with routine sampling versus excess cases versus outbreak. And here's where the 50,000 CFU per liter really jumped out as a threshold of imminent outbreak concern, but this is a really high number and it's better not to live dangerously. So the suitable action level is let's say, you know, probably somewhere lower than 50,000 but greater than zero. And in the EU recently they went with 1000 CFU per liter. But it's important to consider that this ideal number might differ from facility to facility. And this, for this reason a monitoring plan that captures the building's baseline can be very valuable for identifying concerns. We also need to remind ourselves that if we're truly interested in preventing Legionnaires disease. Most of it is not outbreak associated but sporadic. So, an important question is, what can we do to better understand and prevent these sporadic cases. One idea might be a national survey of some sorts to help better inform monitoring and regulatory requirements in the future. And to do municipal distribution system monitoring what might that look like a big challenge here is that Legionella really doesn't tend to grow that well in distribution systems as it does in premise plumbing. So widespread Legionella testing could be very costly and probably wouldn't reveal much. We know from Flint, and now from Quincy Illinois as another example that disruption to the municipal water treatment and operation can be a key contributing factor to outbreak. So one fruitful way forward might be to focus monitoring around such disruptions as lapses in corrosion control storms water main breaks and construction events, and such events if they're reportable to risk, high risk systems and the public for anyone who is an at risk individual then you can upscale the monitoring or take precautions. Additionally, municipal water system monitoring could be centered around high risk portions of the distribution system, known to have high water age and be prone to low disinfectant residuals. So perhaps analogous to the lead and copper rule. I would note that the water research Foundation also has an ongoing project looking into developing strategies for water distribution system monitoring. And that'll be worth paying attention to and I know Mark Lechevalier has more to add to this as well. So where do we monitor and promise plumbing. I'm going to leave that to Michelle Provo later on to enlighten us, but for now to make the point that it's complex every building is different. And it's no easy task to identify and capture and monitor all the relevant risk points in one go. It's important to consider what we do with the numbers. Do we pick a firm threshold like 1000 CFU per liter. As, as Joan mentioned that was a QMRA derived goal for faucets developed from the report. And it's also the EU directive threshold. Or do we recognize that every building is different and that the ideal level might be higher or lower in some buildings and locations and depending on the resident populations and kind of a knowing our building and getting a finger on the pulse and working to control numbers to the extent possible and mitigating when there's an anomaly. So here's an example of how QPCR might be applied to verify that a mitigation is working. So in this lab scale water plumbing study. William Rhodes operated one system in the ideal temperature range for Legionella growth and showed L pneumophila gene copy numbers increasing with time, especially in taps with low water use frequency. In the experimental system he then increased the temperature incrementally and you can see L pneumophila gene copy numbers decreasing, especially at the more frequently flush taps. And this is just an example to show that even QPCR. It can't directly tell the difference between live and dead cells but with time can indicate that a mitigation is working. And the quantitative and high throughput nature of QPCR makes it useful for this type of a screen and if necessary can be followed up and targeted by culture. Another core dimension that cuts across all of this is whether to sample the biofilm or the water. And we know that this is where the action is it's the biofilm as far as Legionella growth, and it participates there in a complex ecology of micro organisms and replicates and it's not likely to be, but for routine monitoring, it's not likely practical to access and it's difficult to standardize and make use of the numbers. And for this reason, water is really the more relevant medium to sample for routine monitoring, but biofilm can be really valuable to sample in an outbreak situation, or for research. And if some of the relevant recommendations from the report mean the first two being part of why we're all here, the recommendations to require monitoring in hospitals and cooling towers, but also to think about broader monitoring to better understand the true scope of the Legionella problem in the clinic and across the US and for sporadic cases and their linkages to water. And as far as methods are concerned, there were some recommendations to further benchmark and test the methods that I talked about here in this presentation, and also adaptations of QPCR that can better discriminate viable strains. There were also recommendations for grounding any standards and targets in microbial risk assessment, including such questions as how to incorporate QPCR based measurements. And finally, putting it all in context, Legionella numbers should not be considered in a vacuum. Again, here's where knowing our system and all the factors that could be contributing to growth, especially disinfectants, temperature, hydraulic factors and as I emphasize today overall system disruptions and potential for exposure is really critical. So in summary, environmental monitoring of Legionella is key to identifying problems, verifying system controls and mitigations are working and preventing the spread of Legionnaires to disease. So if we move into our panel discussion. We need to think about what our framework for environmental monitoring should look like what to monitor where to monitor frequency of monitoring action levels and how to implement. And I apologize if I raised more questions and answers but I'm hopeful that further questions from all of you and the panel discussion can help us to sort all of this out. Thank you so much. Amy that was terrific overview. And it sets the stage for this next part of the discussion today. And I should mention that this is a discussion. There will not be any report or product, but this presentation will be available online and we'll mention that. And where you can locate that presentation at the end. So let's move into the panel. We've got Paul under villain women. We've got Chuck Haas and Mark Lechevalier. And we got a series of questions that kind of Amy led us into that we're going to start with. So we'll put that set of questions up. Here's the view. Eric, hopefully the view is in the center stage. Paul, do you see the set of questions in the center of the screen? Nothing in the center. All right, very good. I must just have my not in the right view. We've got four questions we're going to pose. Should numbers be based on Legionella nemophila or Legionella species? So at the genus level, or other species included, what analytical method should be used. If molecular methods are used, how would the action levels or thresholds be recalculated? And how do we refine the numbers depending on the type of building water device or exposure route. So let's start with this first question. Should numbers be based on Legionella nemophila or Legionella species? Paul, why don't you start off and give us your sense of this. Okay, that's, that's fine. Thanks, Joe. I must say also in the committee, there was a lot of debate on this issue should we monitor for pneumophila or for Legionella species. There are two important aspects to this question. And that is, if we say we focus on Legionella pneumophila, does that mean that we will miss a lot of other Legionella infections that are occurring. And the second one is, maybe Legionella species monitoring is a very good indicator for Legionella pneumophila. So to the first of these two aspects, so will we miss a lot of Legionella infections when we focus monitoring on Legionella pneumophila. It's good to know that in most countries it's seen that more than 95% of the Legionella cases that are reported are caused by Legionella pneumophila. So what the WHO has to do with the fact that in a lot of hospitals around the world, people use the urine antigen test to see if somebody is infected with Legionella and that test only detects Legionella pneumophila. So we still might miss a lot of other Legionella species infections due to that. But there are some countries where they also monitor by cultivating. For instance, in Denmark, if the patients which they suspect to be infected by Legionella, they also try to cultivate. And also in those countries, we see that more than 90% of the cases are caused by Legionella pneumophila. And I also think that the research that has gone into the virulence factors of these species also show that Legionella pneumophila seemed to be more virulent than other most other Legionella species. So if you look into the science of this, you could say that Legionella pneumophila is for sure a problem because a lot of people that are going to the hospital with this kind of infections are detected as having Legionella pneumophila. For the other Legionella species, we are not so sure. So there are some indications that that might be less, but maybe we miss them. But still, I think that we should focus our focus on those pathogens that we for sure know that they cause problems and in this case it's Legionella pneumophila. So in my opinion, it's good to start focus on Legionella pneumophila monitoring and not so much on Legionella species monitoring. And I think it's already a challenge to get Legionella pneumophila under control. And we have done that we can decide to start looking for other Legionella species that might cause disease or even other opportunistic pathogens that can be present in a premise plumbing because I think that's micro bacterium avium or say the monastery can notice I might even be more important than some of the other Legionella species. Yes. Chuck. What are your thoughts about this monitoring from your perspective. I think the key is to be able to monitor frequently and cost effectively. And if a Legionella species methodology facilitates that rather than looking at Legionella pneumophila. I think one shouldn't turn down their noses at that. I certainly agree with Paul that, you know, the Legionella pneumophila is what we know now to dominate the health effects but we need to temper that with the fact that many clinical cases of pneumonia are not the ideology is not really known. And so that represents a great uncertainty, but the key is really monitor vulnerable sites with relatively reasonable frequency. Yeah. And Mark from the water utilities side are they interested in some of these other species I mean they're there's 61 and we know about at least six or seven have been associated with disease. And I think the question here is of course where are you monitoring in clinical settings. That's where these other Legionella species and largely associated with illness so you have in ICUs under cancer chemotherapy organ transplants where their immunocompromised virtually all of these other Legionella species have been associated with infections in that kind of environment. So now you're talking about well, is it is appropriate to have a target for a distribution system or, you know, a building or school where you're outside of this immunocompromised setting so I think I would certainly favor hospitals and nursing home places where you know clinical environments where we have immunocompromised high population and compromise individuals to do monitoring for all the as Amy pointed out, more than half have never been associated with, with, with illness. So, you know that we're casting a broad, broad net. And as Paul pointed out, many studies in Europe in, you know, around the world, Legionella is predominantly the, the target organism. So I think it's appropriate for distribution systems and buildings to focus on the highest priority would be Namatha. Now that opens as Amy pointed out, a lot of commercial methods simple methods that are rapid and more usable than than the, you know, the ISO the standard culture method, which, in theory, detects all Legionella but in fact, studies have shown it was designed predominantly for Legionella motha. That really leads us into this second question, which is, you know, actually, if we can put that up on the screen, what analytical method really should be used right because we've got some that are species specific and some that are genus. So maybe you could address that a bit and then we'll, we'll get to our other panelists on this question. Sure, what I was saying is that the culture method, you know, people think it detects all Legionella but in fact studies have shown it's predominantly focused for Legionella motha. And these other species, it recovers at, at, at variable rates, particularly when you add often a pretreatment which is an acid or a heat treatment. Again, that was designed primarily for motha and, and you start losing these other species. So it's amazing that there's relatively little work in this area, but, you know, certainly the culture method now doesn't detect all Legionella species. If you were really wanting to do that, then a QPCR approach has, has been done. We published paper a couple of years ago, looking at this in reclaimed water, and by QPCR we found all kinds of Legionella species, but the culture was 95% of the Legionella we got from culture was Legionella motha. So there, this method certainly give you a bias of what kind of organism you're going to find. Yeah, that's right. Paul, what are they doing in Europe in terms of methods and methods development or application of different methods? Well, I think in Europe it's more or less similar as in the US. So, but in the countries that have the regulations with the Legionella is one of the parameters. In, I think all European countries it, it is obligatory to do cultivation methods, according to ISO. So that's mainly used, but that has a big drawback in my opinion. And that is that it has quite some time to results. It takes seven days to get a result. And of course if you have Legionella motha in your system you want to act much faster. So there is a lot of debate going also on in the Netherlands, if in not only in the Netherlands because as the country where I live, but also in other European countries, whether or not to include QPCR as a method. And as Amy already explained, one of the drawbacks with QPCR is the problem with life and death. So maybe your system was colonized by Legionella motha, but you use some kind of control measure and they were all killed and maybe QPCR is still positive. And you won't see that with cultivation, but I still think that QPCR can be maybe a first method in monitoring to see if your system is negative, because if your QPCR is negative, you know everything is fine. And then if you start your QPCR monitoring and you find Legionella or Legionella motha, you know something might be wrong and you can start cultivation to see if the bacteria are also alive. So I think this is a nice strategy where you can combine methods for monitoring, but you don't have to do all the cultivation for all the samples you are taking, because most samples in Europe are always negative for Legionella, luckily, if you use cultivation. So it's sort of an adaptive monitoring type approach. And are they implementing that starting with QPCR now and then depending on the number that comes out of the PCR assessment moving to culture, do they go ahead and send it off for culture immediately? So it's not in the regulations, but a lot of companies who have large cooling towers are also wastewater treatment plants which we have seen in the Netherlands can also be a cause for Legionella outbreaks. Those companies, they include the QPCR as well as their normal monitoring you have to do according to the regulations, just to have more often sample screening and also to get a quick result from that. Yeah. Yeah, so Mark, in the water utility, are they thinking about these kinds of strategies? Are they looking to Europe? We lost Mark. Chuck, why don't you, from your perspective, you know, we're talking about, sorry, Mark, you froze for a moment there and I just switched over to Chuck. We'll come back to you. Chuck, go ahead. You know, we're talking about trying to take research and new methods and put them into practice, really. Well, I think there's a barrier in terms of incorporating research into practice that exists, you know, well beyond simply the Legionella consideration and that is liability. You know, if somebody uses any sort of method to monitor any sample where there could be human or ecological exposure and you do see a hit, then what does that really mean in terms of your liability to remediate or mitigate? And so that's a universal concern that we are up against. Hey Chuck, Mark, let's get back to you. I think you're lying again. I mentioned there's certainly roles in utilities would do operational monitoring to validate the real-time operations and then it might do other types of monitoring to validate the controls. And so I can see. Would they use different methods you think for that? Certainly. I mean, you know, utilities might be monitoring particle counts, for example, to measure, you know, performance of filters, but the regulatory measurement is turbidity, for example. So one might use rapid methods to get, you know, a sense of operations, but a culture method, for example, to validate that everything is working. You know, clearly the time is a factor when one would like to have it as soon as possible, but, you know, the validation simply tells us what's happening now and real-time is adequate and, you know, and I know, I know what's happening in my system. But to Paul, though, it says, you know, Legionella is monitored. I mean, I refer to a report by a Vandepore, which found Legionella species in like 97% of buildings in the Netherlands, but only 1% was in the Mophila. So when you said they don't find Legionella in water systems, I presume you were talking about Legionella and Mophila, which is more rare. But again, I mean, I point to a study by New York City presented last year by PCR, they found Legionella species in nearly all of the distribution system samples they collected, but rarely Legionella and Mophila. So again, I think that the Mophila would be appropriate monitoring for water systems in buildings and then a more inclusive monitoring for clinical environments. Again, all of this is related to your water management plan and the levels of control that you have. And so if the controls are working and they're specifically want to make sure they're working for the known pathogen, you know, that would be a starting point. But if we get better methods down the road, you know, that level management can be expanded. Yeah, I always think about that, you know, these methods have to be like Chuck said, easy to use because while outbreaks, you know outbreak investigation is that we're going to move forward with, with, you know, all the tools maybe in the toolbox. But most of the cases are sporadic. So, you know, and that could be very widespread in terms of where you monitor and how often you monitor I think cooling towers sort of have a system but, you know, approach but it really seems like we're going to need all these methods and gain some experience in different systems on what they, what they illuminate in terms of Legionella and genus, the genus and also the species. So the concern is that in some places where there starts to be mandate like in New York State mandates hospitals and nursing homes. And for all Legionella species that may be appropriate there, but picking that up and putting that into office buildings or water systems, you know, from a clinical setting to a non clinical setting. We should give some thought that is that really necessary does that really meet our process control needs. I think check how we're going to build this database, especially if we want to use QM array we go on to this, the next question. The, this third question, and how are we going to, you know, really use these new methods which are going to provide more maybe more information higher throughput. So if we can go on to that third question and molecular methods are used. How do we develop, you know, action levels and thresholds and how do we use this for QM array. Well I think first we need to, as you say Jonah larger database in terms of understanding what the relationship is between the molecular signals and viable cultural both mic organisms. And you know the question that I would give and the data do need to be developed but there's a lot of metadata that needs to be collected as well because that ratio will undoubtedly depend on the conditions that the bacteria have encountered over the course of time prior to sampling and detection so we need to record that and ascertain maybe one set of ratios are good for chlorinated systems and other set of ratio for chloraminated systems, and so forth. Yeah. Paul, what about using these, you know, viable molecular tools to go in and investigate, you know, risk, and, you know, places like cooling towers where there's a constant disinfectant. You mean with the viable molecular, molecular tools. Yeah, yeah. And can we can we really look take those new approaches and look at risk. Okay. Yeah, well, so I think one of the things that is really missing in the scientific literature on this molecular methods is the link between the numbers you get from qpcr and and the risk of disease. So this has been established for for the cultivating methods so we know that quite well, but it has not been established for for these QPCR methods for instance. And at KDL we are where I work in the Netherlands. We have done a study where we compare the numbers of bacteria with with flow cytometry with culturing with those that we find with qpcr so with the gene copy numbers and we saw some interesting things there so gene copy numbers are always higher than colony forming units or or just cells counting by flow cytometry. But we also saw that that depends on the bacterial species you are looking at. So we have done E. coli and Aramonas and we see that for E. coli it's like 10 to 100 times higher qpcr numbers than cell numbers. But for Aramonas it was 100 to 1000 times higher. And we also saw that it was depending on the growth phase these bacteria were in so if they were in the exponential growth phase, they had the qpcr numbers are much higher than if they were in the stationary phase. And it also means that it will be very difficult to recalculate these these colony forming units back to keep PCR numbers. So I think we really need data on the relationship between qpcr numbers and risk of infection to be able to get to get to some kind of very reliable threshold values for qpcr numbers. So that's, I think that's one of the big challenges. It really sounds like we need this database and just a lot of different, you know, venues and systems. You know, as Amy pointed out, these different buildings are very complex. And we've also seen these community kind of widespread impacts. Mark, what's what is the utility I know Amy mentioned the water research foundation. How are they looking at these new molecular methods and and thinking about risk. There are, you know, it's still, I think it was we're saying that it isn't an area of research to try and understand. Of course, you know, there's needs to be molecular methods, sometimes is more of an art than it is a science and it does vary by laboratory to laboratory. So having that kind of consistency, having you know, results that are that are comparable across different platforms and the rest is is important. And then, ultimately, taking it out of the research laboratory, and you know, packaging in a way that users in the field could use that and Amy showed, and there is an explosion of different commercial products that are coming to market that can help in this and I. I think it's very exciting that these these tools become available and I just would be concerned that we don't have regulations or, you know, requirements first that would limit the ability to use a method that is Legionella and Mophilus specific and say, oh, we can't do that because it doesn't do this, you know, X, Y and Z. We need to have the methods. We need to have experience. We need to have more data. And I think empowering utilities and operators and building managers to be able to get this information is the only way we're going to get this information in a situation where really has sufficient information and start making these kinds of decisions. So the research foundation is working has worked on a number of projects they're working on on some more participate on a project, particularly around communicating these results. It's another, you know, there's a certain fear to do this testing because we don't have any framework to put these results in. So there's a lots of different facets to this question of monitoring and and what do I do and how do I respond that I think people in the field are crying for direction. So, so the researchers, the, you know, the regulators need to step up and provide that kind of information because I think there's a desire to do the right thing. So it's not the, it's not the first time we've had pathogens in water where we, you know, had to use methodologies that did not give us viability. Cryptosporidium is a good example and we really focused in on on treatment performance norovirus is another one. Check, I was wondering whether, as they're going to be approaches where we could do use culture plus PCR and a dose response experiment with animals as was done for, you know, to a certain extent for for norovirus I mean we have an animal model, which resulted in a dose response to MRA, right? Well, and they're having animal models, animal models for Legionella. You know, I guess my inclination rather than repeating dose response studies directly with QPCR, which I think Paul was implying was was to look at ratios and environmental samples that were concerned with. And then use that ratio to anchor the dose response to an imputed environmental concentration of infectious viable organisms. Yeah, I think that'd be quite interesting. I know that I've seen some recent data that the species by QPCR or maybe 1% or 0.1% of the, you know, the genus PCR numbers and then you could add the culture in there as well. But you have the, I suppose the issue of these other species maybe not growing as efficiently on our culture systems in our culture systems. So a lot of work to do I think to make sense of that. Let's go on to this last question. And this really I think we're trying to get at, you know, we're going to go into different buildings I think maybe Mark you already, you know, kind of mentioned this. You're talking about a hospital or a nursing home versus, you know, a residential or business office. You know, there might be different numbers. How are we going to get at that, or even at the device itself versus the building water quality versus at the tap or various devices that might produce these aerosols or diminish the aerosols. And I think, you know, we've come to two different kinds of questions. What is the health risk of, you know, different concentrations and the exposure and the route of exposure is certainly an important area. The second part can be related but doesn't have to fall into the same level of scrutiny is saying, what's practical and on a management scale, you know, I may not know exactly whether or not exactly what the risk scale is for different concentration, but I do know that I can manage these concentrations these occurrences at different levels. And while I'd like to know the health impact so that, you know, I can be informed by some QMRA analysis, but what I do to manage the concentration, I know I'm moving in the right direction to, you know, to manage health. And so, you know, we can move this out of a public health question into just simply a process control process management. And I do think that we have international guidelines and experience for what works in the field to, you know, to start to move in this area. And I think it's really important just to get us out of the starting blocks that we have some kind of guidelines around management that could be informed by public health, but, you know, provide some guidance to managers in buildings and water systems, you know, that they would know that, you know, I thought like our 50,000 is certainly problematic, you know, other levels could be said to say, you're starting to lose control, you know, we're not sure exactly what that risk is, but you can do better, you know, properly manage systems generally can do X, Y and Z. And I think that kind of guidance would be really helpful. And I started to work on that for water systems. I'll talk about that when we come back after our break. But Chuck, maybe you can address this because when you think about the numbers that came out of the risk assessment for like showers versus taps, you know, these different, you know, they produce different aerosols, different kinds of risks. But in essence, you're going to be remediating probably a building, I would guess, or a cooling tower, you're not going to remediate at the individual tap. Right. So, how, how are we going to reconcile these because their numbers are pretty far apart. And we understand that, I mean, scientifically, because it's, you know, the amount of aerosols being produced, but I mean what you know one might start thinking about in the microbial risk world which we haven't really done before is to borrow a tool that they use and chemical risk assessment that is to talk about attributable fraction. So, you know, what attributable fraction of the allowable risk is appropriate to say might come from cooling tower exposure from showering from miscellaneous aerosol devices in the household from building architectural features to name a few, and then use the QMRA approach with the allocation of whatever an acceptable risk level is, whether it's one in 10,000 per year, one micro dollar or what have you, allocate that risk amongst the various sources, and then you can get down to a criteria based on the type of exposure. Yeah. And, and, and Paul, this leads me to this kind of question and I know it was brought up in the report as well as is the issue of aerosolization. And the number, you know, that we actually get exposed to an aerosol versus what's in the water column what's in the biofilm what's in the amoeba. Is there some way we're going to look at these different numbers ultimately for remediation and are we going to start looking at remediation of amoeba as well. Is that going to potentially help us. Yeah, that are good points to to raise I think especially monitoring what is in the aerosols is still not done very much. So actually, there is not much data on how much Legionella plamofla will be in aerosols. Some of them are done on showers, but if you talk about cooling towers or wastewater treatment plants that that's for sure not been done very well there is some modeling but not real measurements. So actually we don't know very well what kind of bacteria that are in the water or in the biofilm will get into the aerosols and cause the problems. For instance, in the Netherlands that that is a big issue at the moment. I explained before that wastewater treatment plans are now being seen as a source of Legionella plamofla. And that's especially true for processes that run at higher temperatures because Legionella plamofla need higher temperatures to grow. But these processes in the in the wastewater treatment plants need to run at these higher temperatures for the other bacteria to move the bad stuff from from the from the wastewater. And the only way at the moment to to control these these wastewater treatment plants is to cover it by a tent or or by a building or whatever. So these these wastewater treatment plant owners are now saying yeah but we don't have to know what's in the wastewater we have to know what's in the aerosols coming out of our systems. Because that's the true problem. So I can say that within the next few years, there probably will be a lot of data coming from the Netherlands on this because it's a hot issue. And there's a lot of money going into there. And I think we really need that data to know more about this way how the bacteria goes from the from the biofilm into the water and into the aerosols in the end. So again, big challenge for science but I don't think we are really there. And you might have seen that that in Europe, we have threshold values defined in our regulations and also in the in the new EU directive that will be probably be accepted somewhere in the beginning of next year. But those thresholds values are not really related to risks, but they are really kind of arbitrary chosen. They work quite well in legislation, as we have done for a lot of other things as well. I mean, E. Coli one in 100 milliliters is also not really related to risk, but was arbitrary chosen. And so I think for now we are really into that area that we cannot really name a number that is reliable for a threshold value value related to risk. 50,000 as we have mentioned in our report, for sure for the outbreaks, but many of the cases, our community acquires and we need to be lower than that, but how long. I don't know. Well, I think it goes to say I mean we've got some management strategies we've got disinfection and adding more disinfection flushing has been brought up use of fixtures systems you know bring in the temperature back up. You know, using special devices. You know that limit aerosols were, you know that that can prevent exposures. You know, maybe each one of you can just end up by making some comments about where you think the monitoring should go from your perspective and just a final final comment there. Mark. We'll address this more in my presentation, but I think from water systems and building systems. I would like to see more monitoring I've been encouraging water utilities through a number of different publications and trying to provide guidance in that regard to start doing some monitoring to do it voluntarily. I agree that they're monitoring their system. They're looking at chlorine residuals. And so, you know, to do this to say I think I'm doing a pretty good job, but I'm going to test that by, you know, collecting some samples and just see what's out there. When we have done that we have found areas with low chlorine that were stagnant, and we found relatively high Legionella levels once the utility do that. They had the tools they flushed that system they put in an automatic flusher to bring that once they had that awareness, they're able to properly manage and I recently talked to them in two years since, you know, doing that study. They haven't detected another Legionella in the system so that that's a success story, you know, they did some monitoring they learned something about the system that made the corrective actions. And, and so I think we're in the stage where that would be beneficial. Yeah, yeah, well we'll hear more from you towards the end of this session. Chuck, what are your final comments. Yeah, I would just add on to mark I think, you know, knowing your system is important and I think we probably know enough at this point, both in utility distribution systems as well as in many building plumbing systems. And also cooling towers for them matter to understand, under what conditions, you might have heightened levels of concern, and to focus your sampling efforts on understanding the concentrations in space and time when those heightened levels of concern exist. Yeah. Paul, your final comments I'll give you the last word. Okay, thanks. And so yeah, I think I agree with you can mark I mean, you really need to know your system I think that's that's the number one. If you don't know your water system in your building. There might be problems so that's the first thing to do and the second second thing is, if you know the weak points in your system, start monitoring for Legionella, or Legionella pneumophila, and see if it's a real risk. If it's a risk, you indeed should try to to control that risk by control measures. But it's not only important to do this for drinking water systems because one of the things that always strikes me if you have Legionella discussions. I think that that is there is much more attention then in these discussions for drinking water systems and for cooling tower water, or for wastewater systems or other systems, because these cooling towers and wastewater systems might be even more important. So that's a great recommendation to Legionella infections and drinking water. So, not only monitor your drinking water system, but don't forget about these other sources also start monitoring there, and how well treatment this infection works to control these problems. Yeah, that's, that's a fantastic point to end on I think, because we do need to, it's an aquatic organism so wherever there's water, and there's aerosols produced probably Legionella. Thank you very much. We're going to take a break now we'll reconvene at 930. And we're going to have some two presentations at that time from Michelle provol and mark the Chevalier and then we'll open up for Q&A. So, thanks everyone for joining us and we'll see you back here at 930. Back everyone it's nice to have a little break when you've been on these zoom calls as we have during this pandemic. And, as you know, I mentioned the 930 Pacific Standard Time and for back here at 1230 Eastern Standard Time. The next session is really going to talk about where in complex systems, should we monitor and why we have two excellent scientists to have contributed so much to this science, and to this and to research in this area, who will be presenting. Now from the previous panel, you know this, this recommendation from the pan from the report about a national surveillance program. It may be quite useful because not everyone can actually monitor or have the ability to monitor a whole variety of schools and different buildings and it's quite complex. So we're going to hear about that from Michelle provol, who will be talking about cooling towers and large systems and then Mark with Chevalier who will be talking about water systems and distributions, distribution systems. So, Michelle, I'm going to turn this over to you. Okay, everything is well. Is everything shared okay. Looks good. Looks good. Thank you very much. Thanks, Joan, for the introduction and I'm happy to continue this discussion. Interesting discussion on monitoring Legionella and the two presentations that Mark and I will be showing you are where and when should monitoring occur and I'll be focusing on proactive monitoring control Legionella in building water systems. So, first, the best way the best approach to reduce risks associated with Legionella is to have a water management plan or management program. The risk management plan really is is aims to prevent and control Legionnaires disease associated with building building water systems and there are many components on the right hand side you can see the Ashley table diagram of a water management program. And analyzing the building, establishing control measures locations and limits, and it includes monitoring basically it's embedded in this program and corrective actions as a response to the any positive measurements and also implementation confirmation by designated team water safety plans, whatever, which are more common internationally are very similar, and, and, and both really want to implement the appropriate management systems to ensure that the risk are added adequately control. So when you want to decide how to test across these very different systems you have to acknowledge the fact that you, there's a diversity of water systems. If you look on the figure from the NASA report you can see how different wastewater treatment plan from a note taps and showers in a building are. Here as well the objective of your monitoring Dr Prudin went through this in detail, but this is really important today I'll be, I won't be talking about outbreak investigation but routine versus determining the need for treatment or meeting a guideline or regulation or mitigation or know you may use quite different tools in in in pursuing these objectives and obviously research which is my favorite would have very many tools so different sampling approaches depending on the objective of the water system so what are the drivers to monitor for your legionella in these systems. What I would say the first driver would would be that it is considered necessary by the risk assessment of your water management plan. If you don't have one agreement and guidance and regulation is quite clear prioritize facilities where control measures such as water temperature or these effective residual levels are not being maintained consistently within target limits throughout the building facilities and the history of Legionnaires disease associated with with their building water system or if suspected or identified cases that the have been identified the facilities that serve vulnerable populations, such as healthcare facilities and within these areas the areas are where it's with highly most vulnerable patients. So how to sample Amy gave a wonderful summary of the methods but basically how you collect the sample in terms of sample collection sample volume holding time and shipping to the lab if you're not doing it locally well first line here and this this table is adapted from her 2020 a recent paper that summarizes these different recommendations and when you look at the collection line you see that sometimes you recommend flushed samples others recommend first first draw no flush so that's quite a difference. Sometimes you flush for a minute sometimes for two, sometimes the volumes depending on the system but also for the same system would be 125 250 ml other times it's one liter and the holding and conditions and the requirements for shipping also vary quite a bit. So sample volumes and sampling protocols and guidance do vary. Does it doesn't matter that they vary. Well I would make the point that it does you can see here the impact of sample volume infiltration on the concentrations of Legionella that were measured on the left hand side you can see the mean Legionella concentration adapted from Hertz 2020 and and in orange would be first draw in gray flush sample using a direct plating, you can see second draws lower, but on the right hand side of that figure. You can see if a filtration is used and the volume is different the values will be quite different as well so the type of sample flush versus first draw and the user filters are important to consider. On the right hand side, you can see profiling sampling from a recent paper from bidard that shows the concentration of the mofila as a function of how much water you flush so first drawing up to 30 liters and for two faucets on the left hand side the blue lines you can see that the first filtration is much higher, especially in one case up to two large higher than the second third and fourth draw in another faucet where temperature control was not as efficient, the all samples were equally concentrated for Legionella so concentration may be higher in first draw. That's the best approach to control for Legionella well obviously test for Legionella, Dr Prudin and the panel just discussed the Genel Primafila versus Legionella species, what kind of standard culture versus the new faster enzymatic culture methods molecular methods, I would argue that cost response time, responding to regulations and guidance and relation to risk are important things to consider. I would also argue that it is way more productive and more in line with a water management program to apply a process control approach, you can measure everywhere, you need to understand how to control your whole system. You would define and monitor operational set points whether they would be for example temperature water heater recirculation outlets these infectant residuals, especially if you have on site treatment. And you may actually look at other indicators I'll talk about that in the cooling tower section and and do consider online monitoring to have a real online type of understanding of how your system is operated you can see on the right hand side these really low cost temperature probes that that can be installed and can no yield a lot of information on what happens in your system. So I'll use the information provided in chapter four of the NASA report strategies for Legionella control, mainly look at examples on how to sample to understand whether main control strategies work in their application different buildings and devices to determine when where and how to monitor these systems. So the NASA report says sites with potential for growth and exposure so basically look for Legionella which could be counterintuitive for some building managers that don't want to multiply the positive results actually you need to do that. If you have limited resources, you need to concentrate on whether the risk is likely to be significant and adjust how you operate your building to minimize that. And focus on buildings that serve vulnerable populations again and focus at risk areas in the building dead ends low usage areas showers that have a lot of production of high production of aerosol electronic faucet TMPs that have been shown to be a higher risk for Legionella. And look at how at risk situation treatment deficiencies you lose your on site treatment you have lower temperatures, short and extended closures that COVID shutdowns right now that we are all living through our extreme examples of that and commissioning start up shutdown cocooning for cooling towers are at risk situation and ideally you should decide these points within the framework of your water management program. So other examples I thought were worthy of mentioning here that there are examples of low risk situations. HSE, which is the UK regulator, gave as examples small bill buildings without people at risk from Legionella where daily water usage is sufficient to turn over the entire water systems or small buildings with only toilets and hand wash basins maybe at lower risk and buildings with a lot of showers and the CDC has a nice summary of it could be sufficient to go for the hot water system but there are situations where cold water samples are needed as well especially in hot climates or in situations where they might be a risk due to how your cold water circulates in your building. So building water systems I'll focus on examples incident in hot water systems for now and they're quite complex there's a diversity of materials submitted to varying water quality temperature flow conditions corrosion loss of residual stagnation so how to focus in there. Well, first of all is often recommended or required to focus more in Europe than here in Canada or in the US, but always identifying their at risk area and selecting a test size after monitoring with, for example, temperature these effect on residuals or area you don't have low flow or intermittent stagnation and you need to include portable sources and all components of your system when you're thinking about selecting the sites. Some general features of these strategies are common but the strategy has to be tailored to each building. And once the system performance is known, then you can determine the frequency for sampling and again focus on points vulnerable to Legionella growth and exposure. So when you want to know your building system it I'll give it a simple example here you need to understand how your system works, and if you do not have a water safety water management program you may not know that but you need to at least have a simplified view of that. And to understand, for example, what is the main primary distribution system part of your building water system and and the secondary horizontal columns or risers or branches that bring the water right out to different areas of the building and the tertiary piping as well which has been shown to be a vulnerable to high elevated Legionella concentration which is the piping right before the point of use. In general, in the guidance they recommend to sample in hot water system near the water heater. Near or furthest outlets on each branch and near or furthest outlets on each loop if the system is loop for cold water point of entry in building and from nearest and furthest outlet as well. I'll give you an example why it's testing is the most definite way to verify controls are working and I'll use two studies here. One longitudinal study in hospital many are presented in the NASA report in a large compliant monitor compliance monitoring database in German hot water system on the right. So starting on with the graph on the left hand side on the bottom, you can see the percent positive, which is quite high and 100% in a hospital after an outbreak where they had temperature at 45 degrees coming out of the heater, water heater. And they increased that temperature to 65 and greater 55 at the point of use and use this thermal regime for 10 years and so that numbers. There were still some background Legionella but but much lower on the right, the big figure on the right is really interesting because we're talking about 30,000 points. What that says is the percentage of sampling that exceed a thousand per liter which is the German standard for Legionella species in this case. And there are three types of points here the circles the red circles are the recirculation loop. The green squares are the sample and the most interesting one in my opinion is the digital sample. The triangles the blue triangles, but this shows is you you have really a cut off around 50 degrees see for recirculation and flush samples, and it needs a little bit more to bring down that number to very low minimal exceedances at the So here sampling really tells you what works. Another way to look at this is to take look at your building and looking at the primary the secondary and the tertiary part of it and and using a tiered approach or you can measure for example temperature or residual if you have an outside treatment. Look at your main recirculation system that indicates the overall system of risk, then you do that for the subordinate return loops to understand know where risk is distributed across the different areas of your buildings, and finally to address the And identifying local issues with defective faucets and showers and that last part is is really important because there have been outbreaks documented related to a level a part of a system that that was not meeting the control points and finally you can decide depending on how your system works where it went to sample when when you have this information. To show again that relying on temperature to know where to sample to to see the to understand the levels that may be present in a large building you have on the left hand side distal points. Positive for Legionella with their number and concentration and you can see that if you look at classes of temperature obviously when you have higher temperatures the very clearly lower on the right hand side, you can see a two liter sample versus a five minute sample is just more indicative of the risers and here again the difference of temperature is is quite important in terms of the levels that can be there present at first first draw or after flushing. Another point that following the very productive discussions we had on methods just before break is is to look at these methods not should I use QPCR should I use culture and I'm showing here the results in measure that at risk points in a hospital after an outbreak. Across a period of 18 months and the numbers in intercourse or QPCR and in darker blue culture. And what can be seen here is that after in February 2015 when multiple corrective actions were taken. The numbers went down very quickly for culture, but they took a longer time to enroll with QPCR showing that it takes a while for your all your multiple corrective action and your process control to really get rid of Legionella in your system. There are challenges in monitoring building water systems when it's one thing to decide where and when you're going to monitor but finding the pipe and without up to date drawings is the real challenge in my personal experience. There's also a really striking absence of logs and online monitoring of water temperatures at control point it is not mandatory in most codes, and it really is needed to understand that operation meets control measures, and almost no measurement of these even in systems within C2 treatment which can be a bit puzzling to understand and accessing sampling location in the different loops is often not obvious you can see the bottom right picture in trying to find a way to sample in one of these pipes is not at all obvious. Also collecting the samples and at different points at risk point is a challenge just identifying all the devices activating electronic type faucet pedal activated faucets low flow spray flow and collecting samples is a challenge. And the general recommendations of removing and clearing a cleaning aerators and shower heads is quite a task and quite important. And I'm going to shift now to cooling towers and share a few thoughts about a sampling for that Legionella testing is most often recommended or required there are regulations in Canada and in the US and just about everywhere else. Because it's an identified cause of outbreaks and also the introduction of regulations has been shown to be effective in reducing the numbers in the cooling towers are detailed procedures for safe operation and maintenance that include at risk period of operations and there are inspection procedures to identify components most at risk. What I find also is that although there are general features common but you have to tailor to your program to each cooling tower. The water management plan will determine the sampling frequency and location regulations typically are every month. But process monitoring is continuous in many cases or weekly and again focus on points vulnerable to Legionella growth and exposure defining an adequate sampling strategy for cooling towers. You have to understand that cooling towers are complex treat have complex treatment regime scale and corrosion and sediment control and the use of oxidant non oxidant biocides that can influence actually culture results continuous versus this continuous treatment. And and often a system shutdown such as seasonal emergency are just to respond to to demands of use for the cooling tower. What I've I've seen and what really is is quite generally use this is a process control approach. And for example I can give you here operator use of these infection indicators such as dip slides for example is quite common. It's not correlated with Legionella but it is a really nice way to monitor this complex treatment regime. And there is a growing use of rapid methods such as QPCR to rapidly give you a response for an investigation and adjustment of treatment or post these infection confirmation. And a nice colorful diagram on the right is the M 15 161 federal guidance in Canada that says basically weekly do a dip slide monthly do a Legionella culture, but also when you these in fact do a QPCR right away so after a minimum time after but to know if your procedure was effective. So, the last thought of monitoring in cooling towers. There's a very well established practice of automated control of scaling corrosion using online monitoring. I think it's time that we look at innovative approaches to adjust treatment to minimize LP be the outcome of what we're doing in cooling towers and I'm showing here an example of an automatic autonomous QPCR based online technology that identified riffs immediately in a no allowing for immediate adjustment of treatment and having low interference for industrial matrices and and these in this person. The graph on the bottom is really interesting to look at before the device was installed you can look at for the first period those are Legionella and GU per ml values you can look at the values that go up and down and little orange circles or schedule and actually shot treatment that was administered and you can see that after a while with treatment adjustment. On the right hand side, first of all the name numbers come down and secondly the schedule shot treatment are no longer needed so again this is your basically monitoring what you want to control instead of indirect indicators. So last slide responding to positive Legionella samples as many other members mentioned in previous talks expect some positive but interpret as per building specific acceptable levels or regulations in some cases. Thresholds need to be adapted to the builders, the building users and features showers faucets toilets do not represent the same risk in terms of able so information and complete absence in a transplant unit is is is not something anybody would like to to challenge. But what about low levels and public building faucets is that something that should be taken care of immediately in in constituted at large risk. The COVID-19 Legionella monitoring that's going on across the US in Canada now is showing some some positivity and what may force a definition of acceptable levels that were discussed by the panel finally referred to your water management plan if you don't have one get one done to be able to implement the corrective action if you have positives to develop reference levels for your system and to know how to communicate with users and regulators. So I thank you for your attention. Thank you so much Michelle we're going to turn this over to Mark for his presentation. Are we looking okay. Yes looks great. Okay. So, so I want to pick up where Michelle left off and emphasize that water utilities have water management plans, as well as, you know, similar to water systems. And these are embedded in a variety of drinking water regulations. So when can think about these regulations in the United States we have surface water treatment rules. So in all form rules I have these in plural because there are, you know, long term one and two, we have disinfection by product rules lead and copper groundwater, and also operator certification unregulated and security, resilience regulation so all of these together can think about a set of activities that are intended to manage, in this case particularly microbial risks, as well as other risks in drinking water distribution systems, as well as there are a different in water industry best practices so we can think about things are generally called the 10 state standards there are the Great Lakes regulations. AWA American Water Works Association has a variety of different standards of practice. There are state requirements, there are fire protection requirements, and many utilities have their own internal set of best practices that go above and beyond just just the regulations require. And there are many activities that good water utilities routinely operate. For instance, while the surface water treatment rule requires maintenance of a disinfectant residual utilities may have their own activities. They might have routine flushing of pipelines to remove sediments and improve disinfectant residuals. They will routinely clean and have maintenance and inspections of storage tanks. Their procedures for pipeline repair and pipeline replacement can be done in hygienic manners and to ways that improve the quality and distribution system. They practice corrosion control and scale control, and these are not only important for protection of the pipe assets, but they have impacts on the microbial quality of the water. In systems that practice chloramination, they would have additional procedures for nitrification control, pressure management, cross connection control, avoidance of stagnation through tank turnover avoiding dead ends and system designs. All of these activities, the regulations, the practice and the activities together, define a whole set of activities that utilities do that generally provide water that is safe and for their public to consume. And so what do they do to validate that these activities are working? Well, first of all, there are periodic sanitary surveys. So in the surface water treatment rule, under the regulations for Legionella control, it sets a series of treatment techniques. And one of these is to have sanitary surveys. So to go beyond just, and so this is something that typically the state entity does. At American water where I was there, we started to do our own internal inspections and we started to pick up what the outcome of the various sanitary surveys and start communicating that to all of our water utilities. This is something that I think EPA and the states could do better. They do a lot of sanitary surveys. They find deficiencies on that. So I think it would be good to publish that so that other utilities that aren't have been inspected can learn from that and be proactively implementing corrective actions. There are required monitoring for disinfectant residuals. The surface water treatment rule says it has to be a detectable residual and 95% of the locations in two consecutive months for surface water systems. Unfortunately, there's no requirement for this in groundwater rule, an area I think is a lapse. They require disinfectant byproduct monitoring for PHMs and HAs to balance this microbial and disinfection byproduct risks. They're required monitoring for total coliforms, E. coli and some utilities do HPC bacteria. There's required monitoring for corrosion control and optimum water quality parameters to make sure that their utilities operating in proper way. And of course under the lead and copper rule periodically there's monitoring to validate that the optimal water quality parameters in fact are delivering water that is protective of corrosion for lead and copper. And there are monitoring for water pressure and water tank levels that utilities typically do. And in addition, you know, realistically, utilities are listening to their customers. There's customer complaints around turbidity, taste and odor, discolored water or water pressure. These are opportunities respond to issues happening in the systems to correct any actions that may lead to water quality problems. And so we think about the set of regulations, the sets of activities, the ongoing monitoring to validate that the water that's being produced is safe and wholesome. And now we address this question of Legionella management because, you know, we've seen year after year increase in Legionella outbreaks. So today, you know, about two thirds of the waterborne outbreaks are related to Legionnaires disease. And utilities recognize that this waterborne, although most of these outbreaks occur in buildings and cooling towers and situations, they have a shared responsibility. What they do provides water to these buildings. And so it's important that they are doing their part of that equation to make sure that all the monitoring, all the process control is happening in the distribution system is adequate for Legionella management. And the problem with this is that, you know, typical fecal indicators that are monitored are not predictive of Legionella nemophila occurrence or Legionella management. And a gap in the current regulations, they can permit up to 5% of the distribution system, not to contain a disinfectant residual, and that's problematic. And we have seen a few outbreaks, one in New Jersey related to a lack of chlorine in a storage tank. And just last year, there was an issue in a distribution system in Maine where part of it routinely didn't have a chlorine residual and related to some cases of Legionnaires disease. So that is an important responsibility that utilities have. And I think the availability of easy to use Legionella nemophila methods as we've talked about, both culture rapid culture methods as well as rapid PCR methods now start to put in the hands of the water utilities tools that they can look at their system and ask this question, am I doing a good job for Legionella management? And one of the biggest problems of this is a lack of guidance on responding to positive results. And so this has frozen a lot of utilities not to do any testing because if we do testing, you know, what do we do if we've got positive results. And so to help this process. I developed earlier this year, some guidance manual on developing Legionella monitoring program, and this is put out as a suggestion for water utilities that kind of, you know, think about this process and kind of get out of the to start doing additional monitoring in their distribution system. And I offer this as a straw man. You can like it, you can hate it, you could propose something different, but it's important that we start this dialogue and we come to some kind of guidance and direction, so that we can validate the activities that are being done by utilities to make sure that we have confidence that they're doing having the result of managing Legionella in the distribution system. So this manual covers seven major steps. I don't have time today to go through the whole thing. You can find it. It's free available on my website. This was also developed in collaboration with the people from IDEX and so it's available on their website as well. It's just a guide to try to help utilities get going. The first part of this is develop program objectives. Why do you want to do this? What are you trying to get out of this? What do you want to know? And so it steps through a lot of different thinking about, well, why would I do that and what do I want to do? Because ultimately the monitoring you do and the tests you do is going to relate to why you're doing this and what are your objectives. The second part is also really important is identify the monitoring team and begin to educate stakeholders. And so there are a variety of different internal stakeholders to utilities, different players as you think about engaging your communications team, you've seen your management, your legal operations of both treatment and distribution. So it steps through the thinking about that and how to engage them. And then it also talks about external stakeholders, your public health regulator, your environmental regulator. In some states that may be one in the same agency. Many states there are separate agencies. The large buildings, your customers, your large customers, your media, NGOs in your community. So it starts thinking about that. I'm going to start talking about in a little more detail how to developing your monitoring program, how to communicate those results and then so focusing on those two aspects right now. So once you've gone through your protocols, you engage it, you have buy-in that you want to do this, you have buy-in on how you're going to respond to that. You could think about, well where do I sample from? And there are a variety of different approaches since this is a voluntary activity by utility simply to understand their system better. One approach would be to use your total coliform monitoring locations. You have lots of data, years and years, reams of data on not only what is the coliform and E. coli, maybe HBC, but you know what your chlorine residual is. You know what kind of normal would be for those locations. And therefore you can take your Legionella monitoring and put that in context of this larger data. So there's an advantage and the total coliform station should be already representative of your distribution system. But going on beyond that, some utilities may want to look at the reservoir and storage tanks. There have been cases like I mentioned where lapses in management of the store tanks have led to outbreaks. There have been studies showing Legionella currents in the sediment of some storage tanks. Utilities may also focus their monitoring on locations of potentially vulnerable populations. So that's not already included in your routine monitoring. You may want to pick up samples near hospitals or nursing homes or parts of the system where there's more elderly populations. Some utilities may also think about their disinfected byproduct monitoring. These tend to be more weighted towards the ends of the systems with longer detention time. So it's another way of thinking about monitoring your system. And I also start to talk about utilities. Well, maybe thinking about their municipal and utility owned buildings, you know, those serve the public. And just as we talked about having a building water management plan for these types of buildings since they serve the public, that might be a way for utilities and cities to lead by example about, you know, having water management plans and having monitoring there. So next part is thinking about determining sampling frequency. This really depends on laboratory resources. So wouldn't necessarily have to do every total cold farm monitoring location every week. But you one can start to focus this on times when there are war warm water temperatures. We found in some studies of drinking water just be systems detection of Legionomofla when water temperatures are warm, particularly in around 25 degrees which for some parts of utilities that may be only during summer months but other utilities in this in warmer climates that may be more common during times of the year. And then we start thinking about well what do I collect. You might want to certainly want to monitor. I think as a starting point Legionomofla, as we just discussed, adding the other Legionella species can be informative but but may give us signals that aren't necessarily related to major health risks. Certainly monitoring for total cold from E. coli to put that data in context and my slide is moving forward I'm not touching that. Certainly want to look at free and total chlorine if you're a chloramine system may want to measure for monocloramine temperature pH and an additional parameters to look at evidence of nitrification. In all cases utility should be following their established procedures and quality control for these parameters. Also then to think about the people that are collecting the sample determine that responsibility the scheduling the training and whether samples flushed or not as Michelle talked about that first flushed samples frequently can have higher levels. But if the purpose of the objective of the monitoring program is understand the quality in the distribution system, then, then, you know, then the flush the sample, like routine bacteriological monitoring that utilities do, maybe appropriate. And to help with this training working with the folks at IDEX with help develop an online education course that's free can log on at that location and can step you through can be a way of training your sam samplers and and people around this this procedure. And then select the locations. What's different about Legionella monitoring is the samples are transported at ambient temperature rather than chilling them because they are organisms that like warm water and then try to process that samples quickly. Ideally, since the location should be collected from water directly from the just the distribution system versus inside buildings and and so that if you had dedicated sampling stations that are direct collected connected directly to the main that can have some advantages. And then I have procedures to follow up. If you collect the sample and find that there's no chlorine you don't want to wait seven days during the for incubation of cultural results to have immediate follow up so have procedures, you find something unusual. It can communicate that and cruise can address that promptly. And then so it's important in doing this to have communications plan. And this is a major section of this guidance document. And I think the stated utility goal is we expect we should have no Legionella mafla and our distribution system, but some research has been done already have shown that even in well run systems, we can occasionally see Legionella mafla at low levels and transient currents and distribution systems. So, you know, expect to find positive results and so I put this out as a suggested guidance. It's, it's my contribution to try to get out of the starting blocks. So if you have low levels of Legionella mafla and repeat samples show that they are negative, then this transitory infrequent detection is not a large concern, provided the rest of your water quality and system operations are normal. If you start to have more frequent detection, of course, this is going to depend on the number of samples you collect, but it's I say, you know, more than 20 or 30% then start to say that even though the levels are low but you're seeing a lot of occurrence, then maybe this is a trigger to start looking at your system and trying to look at well maybe what's going on. Are there any deficiencies to have any kind of main breaks have done any kind of flushing any kind of activities that might be related to microbial occurrence. And then if they're in these more intermediate range between one and 10 per mil or 1000 to 10,000 per liter. This indicates that conditions may be favorable for growth. And now it's time to start taking preventive action so look at there's low residuals, maybe go to flushing the system cleaning the storage tanks, taking activities and this would be a time to engage the public health regulator and conduct a system evaluation, we already have this precedent under the total form rule to do a level one or level two assessment so the similar kind of approach, but looking at your system could be done for Legionella management. That would suggest if Legionella is greater than 10 per mil, still lower than this 50 per mil or 50,000 per liter. So you're starting to have action levels here that are below this level, then it's starting to say, you know, you don't really have control of your system. It's favorable for growth. And now to increase this effective residuals start the flush, engage the environmental regulators and start engaging the public and notification. Oil boiling the water isn't, you know, the same as it's because this risk was not necessarily drinking, but certainly advising elderly and immuno compromise around activities they could do to protect themselves from air cessation of the water. And I think a key part of this is the communication part program so consider posting updates on your Legionella monitoring, engage stakeholders as we've talked about, consider including a statement on Legionella and your annual or biannual consumer confidence report. And the water research foundations we talked before has done a number of projects in this and I point you to project 4664 but it's not customer messaging on operative pathogens and plumbing systems has a lot of templates for doing CCR reports for doing customer engagements for setting up a web website on your utility web page to engage customers around Legionella and Legionella management. And so part of this project and before I left American water, we set up an example that's still on the American water page. You go to amwater.com. Look at the search for Legionella there you can find some an example that was developed for this research project on engaging various stakeholders your homeowners, your large building your healthcare facilities on Legionella. So I think for utilities Legionella is increasing public health issue, one that utilities and their customers should be aware of. There are methods available to utilities that are easy enough that utilities can validate their own treatment processes for Legionella control. Guidelines and training are available to help you get out of the starting block. It's important to engage your regulators and your other stakeholders in this process to shared responsibility and should be proactively communicating with the customers on Legionella management. And as several speakers already said, this is particularly important now during the pandemic when we have stay at homeowners and where large commercial buildings may have more stagnant water that highlight these concerns so they're highlighting the concerns in the buildings and very invariably it's going to ask the question, what kind of utility doing, what kind of data we have in the systems, so it's time to become proactive on that. So with that I turn that back over to you, Joan, for our question and answer. Thank you, Mark. And thank you, Michelle. That was a great overview and thank you audience for hanging with us and submitting the questions. In addition to having Mark Lechevalier and Michelle Provo here and Amy Prudin is still with us. Chuck cost and Paul Vander wheeling on we have other committees, members that are here to help answer questions, including John Lutz and Michelle Swanson and Ruth Berkelman. So, let's get into this into the Q&A. Michelle, I got on the first question Michelle Provo first question for you I think during this pandemic. Everybody's staying home there's a lot of buildings that are not occupied. The water is not being used. Could you address this issue of stagnation and how widespread Legionella might be in these plumbing systems and what do we know to date? There's some several other things that comes to mind here too. Should we be flushing more routinely because of these unoccupied buildings because of COVID? Yes, Joan. Actually that's a really hot question these days because we've never faced such long stagnation times. These shutdowns are so long and even when buildings are reoccupied, sometimes it's just a few people just partial use. So, yes, there are issues and there are many guidance many focusing on Legionella that have been issued in the last six months. And I think the and all wanting to concentrate on flushing and shot these infection of these systems and I think the data is just coming out there about 15 studies going on. Purdue launched a collaborative group and I'm part of that group and conducting these recommissioning studies and we will have data to show is it always bad or does it depend how the building was before? In my personal experience in the number of buildings, sometimes it's fine and now you hardly get any Legionella and in others it can be quite striking, extensive high numbers in showers. So, yes, I think this will push the industry to have these levels that are manageable and to implement the water management plans that are so needed in these buildings. I'll mute there. Thank you so much. Paul, there's quite a few questions that remain about PCR and culture method and how we might use these either in simultaneously or, you know, in a maybe a sequence. And how do we adapt, you know, these are, how do we mandate culture methods, you know, for different environments? And should we be mandating that both QPCR and culture methods be used in these water management plans? Yes, absolutely in favor to mandate also the QPCR methods in these management plans. But of course, I don't know the situation in the US, but in Europe, it's difficult because of the regulations and that the National Health Institutes that advise the governments are really focused, they focused on the culture methods. And I'm not quite sure why that is. I think it was the golden standard. But it has a lot of limitations as well. But they still think that the cultivating methods are a better indicator for for public health risks than the QPCR. But I don't think that the data is there that really shows this. So, I mean, there is this issue of viability. Again, I think if you start monitoring with QPCR, you have much faster results. The negative is a negative. You don't have to worry. And when it gets positive, it's time to take action and one of the action points can be to cultivate in the next round. So that's really mine. I think that's the best way to proceed in this. You know, Ruth, this brings up sort of a related question, you know, in terms of monitoring during an outbreak, because, you know, you might want to isolate the organism and this type of thing, but you need rapid results at the same time. And a lot of health departments, local health departments may not have the capacity for this, or they may miss certain things just because they're looking just for pneumophila with the, you know, your urinary antigen test. Can you comment on what we think health departments should maybe be doing under these circumstances? I'm not, I'm not sure exactly what you're getting at. So during outbreak investigations, what, what kind of advice can we give health departments about monitoring using PCR culture methods? Yeah, I think during outbreak investigations, they usually are Legionella pneumophila because that's usually what they're detecting. If they detect other species or other cerebrates, it's usually because they're doing cultures on bronchoscopies or something systematically, or there's a clear outbreak where they have to look elsewhere. But usually it is Legionella pneumophila, and I know New York City used the PCR and they screened cooling towers that way, and then as Paul said, they then targeted those to culture them. But that gave them a very rapid way to, you know, they have thousands and thousands of cooling towers, so it really was helpful. Yeah, so there's some, there's some precedent there, we could use that as guidelines for other health departments that haven't had to go through the process that New York has gone through. But you can, if you have, you know, epidemiologically, if you actually figure out it's probably one of five, 10 cooling towers, what New York City did was go ahead and culture simultaneously to the PCR. Yeah. So, so Amy, this goes to, you know, I know you were involved with the Flint outbreak and, you know, if we have these widespread kind of community based outbreaks and it looked like there was a lot of respiratory disease. You know, how do we look for the broader universe of opportunistic pathogens? What should we be doing? Is there, is there information on, on, you know, monitoring in the under those circumstances and, and, yeah, just this trade off, I guess. Yeah, that's a million dollar question. And I think it really speaks to the fact we have a safe drinking water act. We don't have a safe breathing water act and there are a lot of other microorganisms in our tap water and fortunately most of them are harmless and quite interesting to as a microbiologist but, you know, others besides Legionella nemophila cause disease so we have other species of Legionella and we have other organisms that are transmitted through inhaling the water aerosols so non tuberculosis lung, non, non tuberculosis mycobacterial lung disease is a big example of that and we could have a whole other Legionella or a whole other national academies report on mycobacteria. So it's a challenge and I think it takes coordination. So, you know, working with folks like Ruth in the public health sector, getting a better handle on community acquired pneumonia and these lung diseases and, you know, what are they, who has them, where are they likely coming from and then linking that with what's in the water. And so my, my initial reaction when I saw those questions was oh no, it's so hard to get our heads around Nella. Now we've got to worry about other organisms and but at the same time, we should be proactive right we've we've lessons and not being proactive with Legionella so the extent that we can coordinate and test the water for other organisms and coordinate with public health agencies I think the more monitoring on both ends and trying to connect the will will give you know the real end goal here is improve public health and prevention of disease. Yeah, I think everybody's wondering whether if we if we implement approaches to control Legionella are we actually going to be controlling some of these other opportunistic pathogens. And I think in some cases we don't know how to answer that. Yeah, so that's a big challenge and in our research, you know we we have the luxuries researchers to look at multiple pathogens so we do try to look at Legionella. Mycobacteria, Pseudomonas, Acanthamoeba, even brain eating amoeba we've done studies on that. And so, so far it is often challenging to find the conditions that work for all of them quite frankly but I think we need to keep doing that kind of work and there's commonalities among these organisms right so they tend to like biofilms, they tend to like warm temperatures, disinfectants help for most of them but you know they have different CT values but you know I think there's there's reason to hope and you know it only makes sense if we're going to go to all this effort to try to tackle as much disease that's transmitted through inhaling water droplets as we can. Yeah. So, so, Mark, the distribution system may be seeding some of these buildings and you had mentioned dead ends and things like this and in your presentation areas where you should monitor. So, do you have data on like geographic changes, warmer climates like Florida compared to Michigan, or places that might get warmer like elevated storage tanks. Should we be testing these different, you know, places in the distribution system, can you expand upon that a little bit. I think it'd be surprising given that we've known about Legionella for more than 40 years, there's relatively little data from monitoring distribution systems that's been recognized, you know, buildings and cooling towers there's, there's hospitals, there's tons of studies, there's actually relatively few that looked at distribution systems so we published last year to studies of distribution systems and and they're well so there's limited data really answer the question at the end of the day. We did look at storage tanks, because we know, you know, that they can warm up you can stratify they may lose disinfectant residuals of the, you know, 1000 or so samples we collected there we didn't see the storage tanks were any more positive than others but certainly that should be an area of focus like I had, I had mentioned. Interesting though we did see more Legionella and Amalfa in free chlorinated systems than we did in chloraminated systems, and in the National Academy report, there's a section, you know, looking at this and there is a curious trend that not only just on outbreaks and on occurrence data, look at this time and time again, chloraminated systems tend to have less Legionella outbreaks, less Legionella occurrence than in free chlorinated systems. And so since in the United States we tend to have more chloraminated systems in southern parts of the United States, maybe that's maybe that's an unintended consequence of disinfection by product, these systems have incorporated procedures that have, you know, you know, I just ironically had less less have greater protector from Legionella. And when you look at the geography of Legionella outbreaks it's that Midwest, and so tends to be more mid Atlantic seaboard. So, where you start to use less chloraminated water. So, we don't really know we definitely would benefit from more monitoring more data. And, you know, like I said, so that will inform all of us so I think we can get out of the starting blocks and do more of that we will be in a better position to answer these kinds of questions. And I always felt that it was important to enable the utilities whenever I've been able to enable the operator. They're far more creative in the questions they will ask than me as the researcher. So I do encourage the utilities to, you know, jump in the water and look at their systems. John, you have been involved in the monitoring of hospitals and I know that you focus on these exposure sites taps and showers and things like that. Is there interest to look at what's coming into the system or the storage towers or other, you know, other parts of the water system where Legionella could be amplifying and then seed, seed taps. Sure. Historically, we've always looked at starting out in water tanks and the incoming source water supplies. I mean, one of the few areas that people really pay attention to is is that hospitals generically have two sources of water coming in. And if they're both open at the same time the flow rates through those water supply lines is not sufficient to kind of keep things moving. So you tend to get some dead leg conditions in some of them. But we look through from the beginning of the system where it comes in from the utility, all the way through to the end distal device and monitor those and culture those areas on a very regular basis. Yeah. Yeah. Well, maybe, Paul, you and Ruth could talk a bit about how do we, how do we generally increase awareness around Legionella and Legionnaires disease. You know, how do we work outside the healthcare arena and interact with building owners, utilities. You know, and work through this sort of complex system where there's multiple partners actually have to be involved to control Legionella in some cases. Paul, why don't you go through first talking about what are they doing in Europe to improve public awareness. So, sadly enough, I have to say that in Europe, the attention for Legionella in the different European countries comes up after an outbreak. So apparently, you need an outbreak of Legionella before there is awareness. That was the case in the Netherlands. We had one in 1999 that gave a lot of awareness and a lot of effort into Legionella and how we can control the problem. But we saw in other countries like Germany, there was not really much happening. Then they in Germany they had this big outbreak with a Bavarian cooling tower. And then the awareness started also in Germany. And that's actually the case in all the countries that you see now Belgium is getting more involved because they had a large outbreak with a cooling tower. So, yeah, unfortunately, it seems to be that you have to have an outbreak before you get the attention and the awareness. The only thing I think that we can do in this is keep posting stories, not only in the scientific journals that we scientists normally publish our results in, but also try to write stories for newspapers or magazines or technical magazines for people working in the installation of premise plumbing and things like that. Because I think that's the only way to get more awareness and also try to convince the people who are in politics that this is a serious problem and that we should take a look at it because it's also a matter that the politicians should be aware of it. And we can think if they can help to solve the problem, but that requires a lot of proactive response of us in the community, you could say. Ruth, what, what should we be doing in the US. It's interesting, Paul is really nailed it when he said an outbreak brings attention to it and you don't want the outbreak so we're doing everything possible to prevent the outbreaks. But it's interesting with the public. One thing we can use coven as an opportunity to say it matters what causes your pneumonia, because often that you know patients get this diagnosis of pneumonia and they never ask what kind of pneumonia and teaching people with coven even that they're various kinds of pneumonia and how you can get it might help with the public awareness but everything Paula said is right. The other issue is that we need to strengthen the health departments and we need to do a lot more in many of the states to tie the environmental health with the public health and in many cases they're siloed sometimes they're different departments, sometimes their divisions within the same. And again New York State and to Paul's point this is probably because of their outbreaks they have done a lot to actually increase of getting the report of a Legionnaires disease case to actually getting an investigated with environmental health, a dual investigation. And, you know, highlighting even smaller outbreaks would help, but obviously the litigation issue is always there too so it's a problem but I agree with Paul and I think there's a lot we can do. Yeah. I think it comes down to some, some cases having an approach for monitoring so we have some of this, these data, even before the outbreak we know that we've got these for added cases and all this kind of thing and, you know, we've got we're learning a lot of new things about the ecology of Legionella and how does this translate how do we translate this to the new testing that we could do, and, and how do we get, you know, the peer reviewed literature into, you know, into a program that certify these methods. Do you have some some comments on that I know you've done a lot on on working on these very sophisticated methods for looking at Legionella. Well you're right Joe, there is a lot that we don't know about the variety of Legionella out there, and there's a lot of very interesting biology, but I also really appreciate the discussion today. There are practitioners that are working on water management plans and, and working with building owners to keep, keep the water safe, they need really high level information that they can use on a rapid basis. So I think the reality is that we're going to need years of research, funding and better communication among the different stakeholders. So we can deliver more specific tests for surveillance and for diagnosis. So there's a lot of work to be done. And of course we're competing with other infectious diseases and COVID certainly deserves the attention it's getting now. And I think harmonizing the PCR method standardizing it in some way for water, you know, is getting, getting these methods certified in some way and I don't know who might do that but that's going to, I think help us move forward as well in terms of moving it into practice moving the research into practice. Yeah. Mark, do you have some, some comments on that, that comparison of culture versus PCR that needs to take place for the water industry to be comfortable using the PCR methodology. Yeah, well, certainly, while PCR is a staple of research laboratories, you know, many certainly of the medium and smaller utilities, you know, that's, they don't do that. And that's why I said, you know, developing a commercial kit, whether it's for culture or for PCR is really important to provide them the tools so that mean that they're competent laboratory technicians, but they may not have they certainly don't have a clean room for PCR prep and all the things that we would normally do in a research laboratory. I do think that the PCR certainly plays a role like we had said, as an operational tool for quick information and know how to adjust the system. And we had some, some success with the viability PCR, we had used the Thidium on azide along with the PCR and we certainly saw a difference in signal here now we know that that's limited UV and activated. There's some report from EPA that copper or silver inactivation doesn't necessarily translate. So I think we should need to have some more development of those methods comparison of different approaches. So that we can have a viability, but we would have to understand the limitations of that of that work. And so, you know, I mean, there's no perfect method. All of them have, you know, some deficiencies as long as we understand what we're using and what, you know, for what purpose and whether the limitations. Yeah, I think all of these methods can be useful in achieving the objectives that different users want to use. So under the Clean Water Act the states, many states have have started to certify and approve PCR methods for beach monitoring. It's a slightly different, you know, approach but we start talking about drinking water potable water. Then we're talking about a national approach and it seems like this national approach might be needed. And the interplay between, you know, the water distribution system and the and the buildings. You know, how, you know, how do we, how do we get there to that to that national level under the Safe Drinking Water Act. Chuck, I know you've you've done a lot with as you look as we look at new emerging pathogens with cryptosporidium and others in drinking water. How are we going to get there with with Legionella. Well, I think, you know, one issue that we're dancing around here is, is where does the responsibility lie and where should it lie for providing safe water at the tap. And I think one thing that became clear with our committee Joan is there's a glaring hole in the Safe Drinking Water Act, in that there really isn't strong enough coverage for a utility or for that matter state primacy agency to have jurisdiction where water quality is maintained within, you know, the last 100 feet from the water meter to the tap. And so I think we need to do that and then we can talk about methods and techniques to do that as well. You know, that goes to what we, you know, we kind of have a framework, and we've used QMRA within the distribution system and potable water but, you know, we get into the buildings. And we're really looking at some of these prevention strategies, temperature being one of the key things I think that came out in the report. Michelle, Provo, I wonder if you could just kind of, how do we balance all this about, you know, the temperature, the scalding, the mixing valves. How are we going to go about making, you know, getting more information so it can make recommendations and they don't seem at odds with each other, and they could, they could move into guidelines like asheries. And balancing also energy conservation and put it in the mix as well. Those are really important points and as the data, it's really data driven and when we work so hard during the committee meetings to look at the evidence from thousands of points in Europe to show what worked and didn't work for temperature. And then we also recognize the risk for scalding which must be addressed and introduce probably another risk, which is no TMVs. So mixing valves in there, but mixing valves like any other device in the building must be managed as to minimize those risks. And that is selecting a mixing valve as close possible to the outlet. A simple one, what that one that can be maintained and cleaned. And hopefully in the future we can find ways to not rely on temperature when we have evidence that other approaches to control in buildings are efficient. When we work so hard to try to gather the evidence that was there, there was no such evidence here, but there are papers coming out every month now and it with long term studies that will help us now find new solutions perhaps temperature won't be needed to be so high in the future but at this point there's no evidence to go in the other way so. Yeah, I'm wondering Amy if you can add on to that because certainly water conservation and water flows water use is all part of this and I think there's enough evidence to know that there's low levels of Legionella that can be found at least by PCR in the distribution system it's seeding the buildings. And so, what do we do about this, you know these this issue of flows and, and trying to implement approaches that decrease the chance of amplification. Yeah, that's a good question and it just everything is highlighting how things are interconnected and there's trade offs and. In the presentation I emphasized how, you know, we think of Legionella mainly growing in the building plumbing and cooling towers and that's where there's the most vulnerabilities but I saw some points in the chat like well sometimes it's coming from the distribution system and. I do think it's important to start looking there and and and times are changing people are using less water right so that there is starting to what you which is a good thing right we want water conservation. But the trade off is, you know, we didn't rebuild our distribution systems for this lower water use so we do have more stagnation and maybe opportunity for growth in the distribution system than we've traditionally considered so you know I think it's important to have initiatives like, like Mark promoted that, you know, we need to start looking there as well. And another big trade off is, is energy is, as Michelle alluded, you know, there, there had been a movement to turn down the temperature and save energy and, well, you know, now we just lost our one major evidence based means of controlling Legionella is elevated temperature so you know that the challenge with Legionella really is systems thinking and thinking through all these details and kind of balancing the trade offs. Yeah. And how are we really going to to get a handle on disinfection and in the buildings themselves I always feel like it's still a black hole, even monitoring disinfection residuals and buildings and maintaining it. So, Mark is the water industry going to give some advice to, to building owners, you know, in regard to both monitoring and maintaining disinfectant residuals this is another issue by its temperature flow this infection. And it is a sticky issue. You know, under the Safe Drinking Water Act, if buildings implement booster disinfection or treatment of the water, you know, potentially they could be counted as a supplier of portable water, and they fall under the regulations and that has been disincentive to do what they know they need to do. And so, you know, under a project from the Association of State Drinking Water Administrators last year looked at all the regulations and it's a bit of a patchwork across the states how different states handle this. But I think there needs to be clear guidance from the states of buildings if you do this, you know, we're not going to create a lot of bureaucracy a lot of disincentives for you to do this, but, and so, and there are some loopholes but, you know, we don't have a Safe Drinking Water Act, I think as people have said, so we do have a gap there and, you know, God knows if we could have our Congress address this, but, you know, absence of that, I think there needs to be, it certainly falls under the state purview, and how that's handled would be a disincentive. I do think, as I mentioned, utilities communicating with building owners around what can be done, what they're doing, what building owners could do is a useful activity. I would just emphasize not having this information, putting your head in the sand is not going to make the problem go away. And, in fact, you know, not knowing and not is not a protection against liability. So, you know, my career American water, you know, with your help we started looking at cryptosporidium and Giardia, we've taken on viruses, mycobacterium, Legionella, all different chemicals and the more that we did that the more people said, you're doing a good job. I think it's definitely having that information and managing that information so that you can manage the discussion is a position of utilities to be in, you know, power and knowledge. And certainly we don't see, you know, avoiding that discussion is not a leadership role, it doesn't protect you, it's not a safe place to be. So I encourage you to, you know, to step out and do the things that you can do to engage your buildings, engage your publics, they will trust you more for that. Understanding that there are, you know, gaps that we don't know yet. Yeah. Yeah. And that means that's going to have to come along with the data and developing more data and hopefully that will stimulate some of these use of these newer methods and better methods. Well, in Europe, it looks like there's some really new techniques coming out that might be useful as screens, the lateral flow technologies and things like that. Are there any comments you'd like to make about how fast those kinds of technologies might come to fruition for use? I'm not quite sure what technologies you're talking about. Well, I guess there's the spark, is it Kala? Some kind of, what's, didn't Michelle present some of the new types of PCR methods or was it you, Amy? I wanted to be able to measure that location. Yeah. On the site. Yeah, so these, but that's not only coming from Europe. That's also coming from, I know, Canada, for instance, maybe also the US. Yeah. There are really new techniques and hopefully they can help us a lot because, I mean, if you're no longer dependent on a laboratory, I think that can also really improve monitoring. So if you can use these facilities on site, and they are easy to handle, not very difficult, then they really could attribute to a better site on what's happening in your water system. I know that the main issue with these QPCR at site machines are that the QPCR in itself is not really a problem. You can do that perfectly on site, but you also have to take your water sample, you have to filter it and you have to extract the DNA from it. And I think that's still a challenge in all these new devices that you get a good recovery of your DNA from your water samples. But still, I mean, they are out there now and I think people are interested. We are also doing projects on this to compare it with normal QPCR in the labs. I can imagine that it really processes quite quickly in the next few years and that also these issues with DNA oscillations can be solved quite nicely. And then if we have those machines, I think it can really help us also in outbreak situations that you can do on site monitoring what's happening. So, yeah, really helpful, but we need, again, more data, more monitoring. Well, that kind of brings me to a final point and I'd like each of the panel members to maybe make at least think about one statement or one point they could end with in terms of development of the National Surveillance Program. How could we go about doing that? How would it be useful, produce useful data? What approaches should we use to get at some of these, the need for data in such complex systems, everything from the source to the exposure sites? Let's see, Amy, maybe I'll just call on you first and put you on the spot while everybody else is thinking about their comments. Keep picking on me. I know. Well, you have so much knowledge in that brain. You say so. Well, an idea does come to mind. I think it actually with the COVID situation, there's a lot of lessons learned and a big one is data sharing. I'm a big fan of data sharing. And it's been really encouraging to see all the communities monitoring the SARS-CoV-2 virus and wastewater and not worrying about, you know, the, like sharing data and who gets up but just putting it out there and sharing methods and standardizing. And I think we can really follow suit with Legionella and it's starting to happen already with some of the stagnation monitoring that's occurred. So I think a platform that people can really start to share. Yeah, that's fantastic. John, what are your thoughts on a national monitoring program? What should we be doing? I think sharing as much data as we can. And I think that the, you know, there's so many variables involved on the building side and in healthcare and all the rest of the places. I think that if we could take some of the lessons learned, particularly those from contact tracing and kind of apply that to when we have a patient in the hospital that tests positive to really pinpoint what the location that they're getting the disease from is. I've been involved with that for years. It's never been, and one of the things that the, one of the gaps that I know the committee identified is there was no direct correlation in any data related to clinical disease and or environmental cultures at the same time. And I think that's one of the things where we need to bring those two silos, if you will, together is to bring the data associated with environmental testing closer to the actual clinical testing. Yeah, the difference between exposure and then outcomes. Chuck, what are your thoughts on national surveillance program. I think the first thing we need to do a standardized methods both for culture based methods and for molecular based methods so that we're comparing apples to apples. You know, we might also take advantage of ways to have monitoring done in a more mandated way. And, you know, let me make an analogy to what was done or what is being done with radon. So many states now require sellers of buildings to do a radon survey. They're not building assault. You know, is it not reasonable in some circumstances to record the same thing for opportunistic pathogens and Legionella, in particular. And the same thing also in terms of using the insurance industry as a tool to get monitoring implemented at least at the point where a policy is sold. Those are those are some ideas that we need to flush out. Quite interesting. Michelle Swanson. I agree that we need to get the stakeholders talking across disciplines and so that the funding that goes into the research to really be targeted at tools that we can put in the hands of the people who are out managing water systems. Thank you. That's going to be very important. Yeah, most of the committee, we have been focusing on monitoring this national system and in water systems and I want to just turn for a second to the issue of monitoring the human side because I think we do have to deal with the diagnostic methods and also the use of the diagnostics which is not ideal in this country right now. We're not picking up the leaders disease. We're way underestimating it based on reported cases and we know that. I also think it's a time to step back and say let's look at other pathogens in water. And we need to have a handle on the human disease side and there is not currently national surveillance. We need to have a handle on non tuberculosis and my go bacteria. And I think, you know, we've talked in the committee about possibly regional centers of excellence, where we have academic research strengthening capacity and kind of as a backbone and strengthening the health departments as well. And it gets back to this tying environmental health to the, the human side, the disease side. Thank you. I know where our time is up. Mark, I want to get quickly to you and then I'd like our two last panelists at Paul and we'll end with Michelle. You're coming from different countries. What advice would you give to the US? Mark, give us a quick sound bite in terms of what you think we should do for the national surveillance and then we'll ask our other members to give us advice here in the US. Well, I think there could be a variety of different ways that could be done. EPA could require this under the unregulated monitoring. Utilities could form together and do a monitoring, a voluntary monitoring. So, but I come back to the fact is we don't have agencies getting out guidance and how to respond. And so, you know, absent that guidance, you know, any detection as a fear. So I think the linchpin on this is get, you know, having consensus, whether that's a scientific consensus or regulatory consensus, you know, having some kind of metric is really important. Yeah, getting back into that yardstick and what number is actionable for which building, when and where. Thanks so much, Mark. Paul, what advice are you going to give us here in the US? Of course, I'm from a country where there is a national civilians program on the agenda for almost 20 years now. I think one of the most important points and that's already been mentioned. So, I mean, the priority building owners, we are calling them priority buildings, meaning hospitals, hotels, and buildings like that. They have to monitor for Legionella. Thinking about the company says to monitor distribution systems for Legionella. They do that very nicely. They report it. And then, if there is a problem, they try to solve it. But that also means that there is a lot of data that is just going to the graveyard, you could say. And nobody's looking at that anymore. And I think that this data can contain very valuable information to see what kind, how often you see Legionella, is it related to building types, all kind of things you can get out of it. So, I think my major point to the US is, if you will have a national civilians program, make sure that you also do something with the data and not transfer it to a data graveyard, you could say. Yeah. Start sharing it and analyzing it. Yes. I'm hearing that loud and clear. Michelle, I'm going to give you the last word. Did we lose Michelle? You're still muted, Michelle. Okay, so coming from Canada, in the province in Canada that has regulations for cooling tower and code that says hot temperature is mandatory. I can say that I think in the US you have a unique opportunity with this, this COVID, these COVID studies to bring this together and to document what works and doesn't work in terms of control measures in buildings. To use common methods, there's already this very interesting initiative based in Purdue that will tell you, give you data if we use common methods on what control measures do work because now a lot of what we've shown in the report are from German data from Germany or from France or from Italy, I think you need US data. It means you need to measure but you also need to monitor how you bring these numbers down so you have solutions that are tailored to your situation. Thank you so much. Well, I want to thank the audience for sticking with us. We're a few minutes over. You can see there's a lot of, I guess, enthusiasm and interest in this area. This really brings together environmental microbiology, public health and water engineering, really to focus on our communities and our community health our sensitive populations. So this recording will be available. All of you that signed up will get an email, and it'll be on the National Academies website associated with the webinar. So I hope everyone has a great rest of the day and happy holidays to come and everyone say, stay, stay safe. Thanks panelists. Thanks committee members. And thanks to the academies for setting this up.