 John is an independent consultant. His training is in public health microbiology. And he's been involved with the Pool and Water Treatment Advisory Group and also the Health Protection Agency, the public health program in England. He has over 30 years of experience really in detection, survival and control of pathogenic microorganisms in the environment, particularly water and air. And he's been involved in so many outbreaks of, primarily legionnaires disease. So he has a lot of experience in that regard. He's also been involved in this issue of control and control of legionella growth in water systems. And he's been involved in iso-methods. So he has a lot of experience both in outbreaks, monitoring and development of these methods. And he's advised the UK Health and Safety Executive in the Health Department and has been involved in WHO. So we've got experience here in cooling towers, industry, methods. So John, I'm going to let you take it over and thank you very much for joining us. We really appreciate it. Thank you for that introduction, Joan. Can you all hear me okay? Yes, nice and clear. And yes, so I'm going to briefly talk about the legislation approach to controlling legionnaires disease in England rather than the UK. Although the legislation in the UK is all very much the same. Since devolution, there are some slight differences between the various countries, Scotland, Wales and England and Northern Ireland in their laws. And so I'm going to be speaking specifically about the laws as they are currently in relation to England. Having said that, the overall approach in the UK to controlling legionella is very much I think the same as it is elsewhere. That is a preventative strategy with control based on our current knowledge of the ecology, not just of legionella itself, but also the supporting microflora and that combined with good management practice. And this is enshrined as you'll see in UK law. Now, when I first started working on legionella around about 1980, there were two pages of legionella specific guidance which were produced by the Department of Health in response to a couple of hospital outbreaks in Oxford and Kingston specifically. But as you can just summarize on this slide, there's been a massive increase in the amount of guidance available since then. In the next decade, up until about 1990, we went up to about 25 pages or thereabouts, in the next decade, we saw up to nearly 250 pages, over 250 pages, in fact, which is more or less where we are today. So briefly, if we look at the evolution of legionella specific guidance in England since 1974, now that predates the first recognition of legionella disease, but it's significant because that was when we had a new act, the Health and Safety at Work Act, which replaced the old Factories Act. And it covers all hazards, chemical, biological, physical and radiological. And as we'll see later on, virtually everything to do with legionella disease or the laws associated with the regulations come under that act. So the first guidance note was, as I said, produced by the Department of Health in 1980. But as with many other countries, we had our wake-up call in Britain as a result of the very large outbreak of legionella disease at Stafford General Hospital in 1985, which was very exciting for those of us doing the investigation, led to a public inquiry, and that's quite an experience, giving evidence to a public inquiry. And the initial response was an extra notice from the Department of Health, our HN86, giving extra engineering guidance related to cooling towers and evaporative condensers because of our observations in relation to that outbreak. That was followed by the first outbreak, the first report of the public inquiry, and then following that, the Health and Safety Executive produced its first guidance note, EH48. Now, in the next few years, there was concern that people were not interpreting the existing laws and regulations appropriately in relation to the control of legionella. And so in 1991, the Health and Safety Commission, which was then the governing body over the HSE, but it's now all incorporated into the HSE, they produced the approved code of practice on the prevention of legionella. So that's the first specific legionella document with any real legal status. As you can see over the next few years, we got new guidance and new additions of the code of practice. And then in 2000, there was a big change in that the code of practice, which interprets, tells you how to comply with the law and the guidance, the technical guidance, we're all combined in this one big document which was still referred to as L8, and now has, as you'll see, recently been changed again. And then in 2006, we had the HSE and HPA publication on the management of spa pools, that's spa pools or hot tubs, and it's commonly known as jacuzzi's to many of us. So in the UK, as in many other countries, there's layers of legislation and guidance, there's an act of parliament, which is the law must be followed, and then there are regulations which interpret some of those clauses in the act of parliament, and they also have legal status must be obeyed. Under that, you have sometimes have approved codes of practice, which tell you how managerially to comply with the law, and then below that is pure technical guidance, and we'll see how this affects, or rather how, what applied, which regulations and acts of parliament apply to Legionnaires disease. So as I said, the health and safety work act was written in 1974, obviously predates Legionnaire and doesn't specifically mention Legionnaire, but it's duties extend to risks from Legionnaire, and in particular, the sections that people are most likely to get prosecuted under are section two, which requires employees and non-employers, I self-employed people to ensure health and safety of employees, and section three, which requires them to ensure health and safety of non-employees so far as reasonably practicable. And then section six also requires substances and articles supplied for use at work to be safe, which is also interpreted in regulation, we'll see in a moment. The term reasonable practicality or practical practicability involves taking proportions proportionate to the risk. Now, this have term or similar terms occurring much UK legislation and has caused us some problems in recent years. The European community took the UK to task in the European court saying that this was a let-out from the health and safety legislation, which the Europeans had then published a directive on the healthy safety, which very much follows our health and safety at work act, in fact, but they thought that that clause meant that people wouldn't necessarily apply appropriate precautions. I'm glad to say that the UK actually won their case in the European court, and the law has remained the same, and terminology has remained the same. So the degree of risk in a particular job or workplace needs to be balanced against the time, trouble, et cetera, taking measures to avoid that risk. This is not a let-out clause, but if there's the risk is insignificant and the cost is disproportionately large, then you don't need to take steps. But in the case of Legionnaires disease, for example, the risks from cooling towers are significant and they can be deadly. And therefore the courts take the position that costly preventative measures are justified. So now briefly look at the regulations. Most of the regulations again, don't specifically mention Legionnaires disease or Legionella. But the control of substances health hazardous to health regulations covers all chemicals, radiologicals and biological substances. So Legionella and other infectious organisms come under this general regulation. And the next couple of regulations you'll see have certain things in common, right? There's a requirement to protect your employees and non-employees. We've already seen that in the Health and Safety Work Act, but a risk assessment is required. Where a risk is identified, if possible, that should be replaced by substituting something which has no risk. For example, you could replace a cooling tower, a wet cooling tower with a dry system. But if that's not possible or not practical, then exposure must be controlled in some way by using control measures and there must be appropriate systems of maintenance and examination of the equipment and the test equipment and control measures, such as automatic dosing equipment and so on. Adequate provision of information, instruction and training for employees and health surveillance may also be incorporated where appropriate. There's management of health and safety at work regulations again that don't specifically mention Legionella, but they're quite important from the point of view of management. And again, you'll see the second bullet point mentions risk assessment assessment and the risk assessment must be written. And it's, well, where there's five or more employees and the advice generally is that even if you have fewer than five employees, it's still worthwhile having a written record. There should be effective planning, organization control, monitoring and review, particularly review and there should be good communication and so on. You can, if you don't have the appropriate competent help within your organization or knowledge, employ external competent help. That doesn't mean that you, the duty holder is divested of all of their responsibilities. They still need to be able to ensure that the people they employ are competent and doing their job properly. So they need some level of education themselves to do that. And there should be cooperation where there's more than one duty holder. Legionnaires disease, maybe if it's contracted in the workplace, such as somebody working on corning towers or hot and cold water systems and sparkles, maybe reportable as under the reporting of injuries, disease and dangerous occurrences regulations as a workplace accident. But Legionnaires disease is also a reportable course, at least since 2010 under the health protection notification regulations to the appropriate health authorities. Now we come to the first and only set of regulations that specifically mentions Legionella and that is the notification of corning towers and evaporative condensers regulations which were introduced in 1992 in response to pressure from environmental health departments and local government departments and public health individuals like myself involved in outbreak investigations. We often spent a lot of time looking for corning towers and thought that if a register existed, it would save an enormous amount of time right at the beginning of an outbreak investigation when it's very critical to examine the potential sources as rapidly as possible. Excuse me. So the local authority holds the register and they need to be informed when the towers are going to be constructed, when they're put in operation and also when they're taken out of operation. Now in our experience, particularly in the last decade or so, compliance with this regulation is really quite good. Way over 90% of towers are usually registered when we do an investigation. The biggest failure in compliance is usually with people failing to report when towers are being taken out of service which can be an inconvenience. But generally it has certainly assisted us in outbreak investigations. So then underneath the regulations we have code of practice. We have a specific one for Legionella, as we see it learned, and technical guidance of which we have quite a quantity. So the current situation now in 2018 is that we have an approved code of practice which as I said before has special legal status and associated with that are four technical guidance documents, HSG 274 parts one, two, and three relating to the control of Legionella in cooling systems on the first, hot and cold water systems part two, control of Legionella bacteria in other systems, sprinkler systems and so on. And in 2017, the HSE guidance HSG 282 the control of Legionella bacteria and other infectious agents. This is the first one that specifically mentions other infectious agents in spa pool systems. So let's have a little look at these Legionella specific documents in more detail. So the code of practice provides advice to the managers on complying with the Health and Safety at Work Act and the cost regulations and the regulations under that act. You can use alternative methods to those set out in the code of practice and also in the technical guidance in order to comply with the law. But if you do so, you must be able to show that they are effective. Code of practice has a special legal status. If you don't follow it, you must show that the law has been complied with in some other way and in reality, most people do comply with it. It applies to all plant and systems containing water that's likely to exceed 20 degrees Celsius where there is a means of creating and transmitting water droplets or generating an aerosol, which is likely to be inhaled and thereby causing reasonable foreseeable risk of exposure to Legionella bacteria. So it includes cooling towers, evaporative condensers, hot and cold water services, humidifiers, air washers, tunnel washers in industry, spa pools, agricultural misting systems, and so on. It emphasizes systems that are normally closed and operation therefore not considered to be a risk, can still present a risk when opened for maintenance. And it applies to all types of premises, shops, offices, factories, hospitals, industrial plant, agricultural establishments, entertainment facilities, et cetera. The only real exclusion are privately owned and occupied residences. If you own your own house, then you don't have to comply with the law. But if it's a rented property, the landlord has to comply with the law. And Allate specifies a series of steps that are necessary to control the risk. There has to be somebody appointed who's managerially responsible. There has to be a risk assessment process to identify and assess the source of the risk. And this needs to be written as we've seen if there's more than five employees. If you can't eliminate the risk by substitution, then there has to be a written scheme for preventing and controlling the risk. And that has to include up-to-date schematic diagrams to enable people to rapidly identify key parts of systems. There needs to be consultation with the employees to find the risks and control measures. And most important of all, there needs to be a good management system with good lines of communication and monitoring of all the appropriate precautions. Everything needs to be recorded and the records of the monitoring tests, whatever they might be, measuring temperature, high-side concentrations, pH and so on, must be kept for at least five years. The written risk assessment when it's replaced by a new written risk assessment also has to be kept for at least two years. And everything should be auditable and you should be able to follow an audit trail by documents being appropriately signed. So a risk assessment should be a living document. It used to be that we said it had to be reviewed and revised every two years. That specification has now gone. Although in practice, if you look at the reasons for reviewing the risk assessment, on large buildings and large industrial premises and so on, it's very likely that a risk assessment will have to be reviewed at least that frequently. So situations when the risk assessment might need reviewing include changes to the water system or how it's used, change of the building use, changes in the building itself, new information that comes to light on the control measures that you use from research or new control measures that might become available. All new information on the risk, if it's shown that a previously perceived risk is no longer a risk or vice versa. If the monitoring checks carried out show that control measures are no longer working, appropriately, if there's changes to key personnel, in particular the responsible person or the management above that or any key individuals in the management of the control measures. And of course, if there's a case of legionary disease or other legionary locus associated with the system. In addition to the risk assessments, the management communication procedures also need to be regularly reviewed to ensure that they are kept up-to-date. There's a requirement that there should be an up-to-date schematic plan identifying key components in the system. Furthermore, training and the importance of training and confidence and ongoing training are emphasized and the new LA has extended the information on the responsibilities of designers, manufacturers, importers, suppliers and the installers so that systems need to be designed so that they are constructed in a way that will hopefully inhibit the growth of legionary and they need to be provided with appropriate up-to-date information and instructions that need to be updated when appropriate as well. And the suppliers of products and services such as water treatment specialists need to ensure that their measures are designed and implemented so that they are effective and safe and they can show that they're effective and they need to provide adequate information to the user and those respects as well. Finally, there's a requirement that you should have a written scheme of action in the event of an outbreak, how you're going to go about testing your cooling towers or your water system and so on. Now in healthcare establishments there's a slightly different set of regulations and acts of parliament. The ones that we've already spoken about are still applied, the Health and Sative Work Act and all the HSE documents. But in addition to that, in 2008 the Care Quality Commission was created by the Health and Social Care Act and this body is responsible for managing all healthcare buildings in the NHS, not buildings, so all healthcare organizations like hospitals, GP surgeries, nursing homes and so on. And underneath that Health and Social Care Act there are some sets of regulations again. And finally, and specifically there's the Health and Social Care Act 2008 Code of Practice on the Prevention and Control of Infections and Related Guidance which is particularly important again in relation to Legionnaire's disease and other potential waterborne pathogens within hospital environments. And then there's also some very again detailed health technical guidance called Health Technical Memoranda and the 0401 is entitled Self-Safe Water in Healthcare Premises in three parts covering the design, installation and commissioning, operation and management which includes details of testing for Legionnaire and other microorganisms and also part C which is specific for pseudomonasal regionosa in augmented care units. So the Health and Social Care Act Code of Practice on Prevention of Infections applies to all registered providers of healthcare. So as I say, hospitals, GP surgeries, nursing homes and so on. And it includes managing water safety, including Legionnaire but also other waterborne pathogens. There's a set of criteria against which the Care Quality Commission judge people and those who wish to be registered need to ensure they follow those same criteria. So by following the Code of Practice, registered providers will be able to show they meet the requirements of the regulations and they must continue to do so. Now the Health Technical Memoranda, the latest version, 2016, it's a development on the previous guidance, it's moving users towards the holistic management of water systems, i.e. the water safety plan approach and water safety groups. Water safety plan approach has originally, the terminology originally applied by WHO. It provides comprehensive advice and guidance to all those involved in healthcare and management, design engineers and so on. And in addition, it's got some information now on climate change and the need for adaption and mitigation of measures in response to climate change. It doesn't just apply to Legionnaire, it also applies to Uruginoza instead of trophomaniacid multifilia, multifilicobacteria and others. It's in line with L8, an HSG274 guidance, that's the HSE document, it's also in line with the healthcare prevention and infection code of practice and appropriate regulations. It gives a lot more information now on the formation of writing water safety plans and the formation of water safety group who will manage the water safety plans and manage water safety in healthcare environments. It's emphasized the importance of competency and the training of not just the people responsible for overall management, but also plumbers and installers themselves. Something that's been in the water industry for a long time but hasn't always been the case in hospitals. Emphasizing safe hygiene practices associated with the use of water, equipment that uses water and detailed sampling for testing. So all of these guidance documents essentially follow the same control principles which I'm sure you're all familiar with. If possible, eliminate the source of the risk that I said before, substituting a dry cooling system for a wet cooling system for example, would be one possibility. Avoiding the water temperatures that might support growth of Legionella, specifically particularly 20 to 45 degrees Celsius. And where there is a risk inhibiting growth either physically by temperature management for example, or chemically by the use of biocides and so on. Sessons need to be designed and operated so you can keep them clean, prevent dirt getting into the system, keep them closed as much as possible and they need to be flushed and disinfected after construction, immediately before occupation that is, and also before and after modification or repair. And systems should be designed and constructed so that they're easy to clean and disinfect so there must be ease of access to the appropriate bits and pieces, easy to remove equipment to service it and to dismantle it as appropriate. As with all systems that use potable water, the materials that are used in construction of Legionella prone systems should wherever possible be tested so that we know that they don't support significant microbial growth. Keeping the water's moving, keep it flowing, control aerosolization as much as possible and limit dispersal, so for example on cooling towers, you would have drift eliminators. So they keeping the system clean and removed dirt and biofilm regularly, again, particularly in cooling towers, preferably combining physical or chemical removal with chemical disinfection. And the new HSG274 part one, which relates to cooling towers and evaporative condensers gives excellent sets of pictures of cooling tower pack to try and explain what a clean cooling tower pack should look like. And similarly for the hot and cold water systems, there are pictures of the inside of tanks, again, indicating how clean a tank should appear for the purposes of the Legionella guidance. In healthcare environments, particularly you need to identify high risk areas. That is not so much areas of the water system, but the population that's exposed to that water system. And obviously it has to be continuous maintenance and monitoring to ensure the safe operation of the system continues, as we said before, with training of star. Now, both the HSE document relating to hot and cold water systems, that's HSG274 part two, and the Department of Health, Health Technical Memorander, advise the water safety plan approach, first described by WHO, I guess, in healthcare premises. And such as, the way I described in the guidelines of safe drinking water. Both hospitals and healthcare premises should have a water safety group, rather individual, which has collective responsibility for managing the risk in the water systems. That group will generally include representatives of the Infection and Prevention Control staff, nursing care, engineers, one or more engineers who are familiar with the water systems and the cooling systems and so on. A health and safety representative, member of the executive management team, probably a specialist water advisor, and possibly representatives from specialist users like hydrotherapy or decontamination, dialysis, et cetera. So that's all I want to talk about, the regulations and as they are existing currently, and I want to move on to microbiological monitoring, which is one of the questions we're asked to address. In the UK, in the HSE documents, cooling towers are recommended to be tested quarterly for Legionella and the target is they should have less than 100 CFU per litre. That's effectively the detection limit for most laboratories when using culture. And also a TVC or head of traffic, aerobic count is 48 degrees, sorry, 30 degrees Celsius for 48 hours incubation, and that's commonly done by a DIP slide, although as a microbiologist, I don't particularly like DIP slides. And there are the targets, there should be less than 10,000 per mil. Hot and cold water systems at Legionella is not required, but it is recommended if there's any doubt about the efficacy of your control region. So if you know there's a failure in your temperature or biopsychontrol, then initially you'll be testing weekly and gradually over time, that frequency of testing will be reduced as you gain confidence that the system is under control. Similarly, where biocides are used as the primary control, and not water temperatures, and water temperatures likely to support growth. So if you deliberately keep your hot water system, that's 40 to 45 degrees Celsius, for example, which will be the highest risk for generating Legionella, then you would certainly initially test monthly, and you might over time gradually reduce that frequency of testing. In hospitals, particularly, where there are populations at a high risk of infection, then monitoring may well be justified, and obviously again, if there are cases of Legionellosis associated with the premises, then testing will be undertaken. This is a table taken from HSG 274 Part 2 in relation to hot and cold water systems, and you can see it just gives you some advice about what action should be taken. I personally don't really like this. I don't think it's specific enough, and what does the majority of samples mean? What does the majority of samples mean? Does it tell you how many samples to take, or what proportion we're talking about there? And there's, we try to get that change in the revision of the latest revision, but it's still being left in that sort of vague manner. If you get relatively high numbers, then immediately there should be some action taken, and that also applies to the TVC and cooling towers. If you've got over a million per mil, then some action is supposed to be taken straight away. In healthcare establishments, again in areas where patients who have increased risks, some point is commonly undertaken. I think strictly speaking, it's possibly not required by the law, but in practice is generally undertaken, and the Quality Commission will take a pretty dim view of establishments that don't do some legionella testing, and certainly pseudo-malice erosioners are testing in the appropriate parts of the building. And Part B of the Health Technica Mirandum, includes very comprehensive guidance on the interpretation of legionella sampling results, and including when using pre and post-fushed samples, it's a very complicated set of figures, which I did think about putting up, but I think you wouldn't be able to read them anyway, but these documents are all freely available for over the internet if anybody wants to look at them. The guidance for spa pools, it's slightly easier to illustrate on the slide, pH and chlorine measurements should be made at least twice a day in hot tubs, which are used for business. That's for example, if you rent chalets out, holiday chalets and each one has a hot tub, then they should be tested at least daily, and depending on the risk assessment, the degree of usage that might be increased to three or more times a day. In commercial spa pools of large leisure complexes, these are pools with overflow, deck-level overflow and balanced tanks, then they should be tested like swimming pools on opening and then every two hours throughout the day. The microbiological testing, jet colony count, E. coli and pseudomonas legionella on a monthly basis, and quarterly legionella in the same way as cooling towers. So, enforcement. Who are the enforcing agencies? Well, the Health and Safety Work Act and the Associated Guidance of Regulations are enforced by two bodies in England, well, in the whole of the UK. That is the Health and Safety Executive Inspectors, and they will enforce in manufacturing establishments generally, heavy industries, hospitals, and unfortunately, you know, reflection on the shortage of funds these days. Generally, there's no preventative inspections undertaken, or very few preventative inspections undertaken these days. It's a complete contrast to when I was a young microbiologist some 30 years ago, the Health and Safety Inspectors regularly went round factories amongst other things, looking at legionella precautions. And the other group is the local government of environmental health officers, and they are responsible for enforcing the Health and Safety Work Act in offices, hotels, retail establishments, leisure facilities and so on. If there are local government-owned premises, then the HSE would be the enforcing body for those. And now, following the 2008 Act and the Creation of the Care Quality Commission, they also have powers of both inspection and prosecution, not so much under the Health and Safety Work Act, but under the appropriate healthcare acts. And they do, unlike local government and health and safety inspectors, they do carry out regular inspections as part of the registration process. And now, in UKlay common law is based on precedence, and there's one very well-known case which is very significant to the interpretation of the Health and Safety Work Act in relation to legionella disease in particular in England and Wales, sorry, in UK. There was an appeal, there was an outbreak of legionella disease in about 1991, as I recollect now, in London, in Kensington, and the Science Museum was prosecuted. And they were found guilty. They didn't cause the outbreak. There was no evidence that they had caused the outbreak, but they didn't have adequate precautions in place on their cooling systems, which were clearly at risk of being contaminated with legionella and managed in a way that would allow legionella to grow in them. They appealed because they said legionella hadn't been found and there was no link to the outbreak, and the appeal was dismissed. And the judgment said it was sufficient for the prosecution to prove that the public were exposed to the possibility of danger, that the risks that harmful bacteria might emerge outside of the appellation, and had exposed the public to a possibility of danger. And the jury were entitled to conclude, as they had done, that they hadn't taken all practical steps to minimize the risk. So how effective is this legislation and guidance? Well, unfortunately, it's very difficult to measure the effectiveness against the background of improving ascertainment of cases. In the UK, just as in much of the rest of the world, we've seen an increase in the number of cases in the last decade or two, particularly since the introduction of urine and antigen tests. So some of this is probably due to under-acertainment privacy, and then there may well be some real increase in the instance of cases. In the early 80s, when I first started working on legionnaires, the Department of Health was funding a very large investigation of the instance of legionella in hospitals and other buildings and cruise liners, for that matter. We got a lot of interesting information, so much of which has never been published. And in my latter years in the Health Protection Agency, we have tried to get funding to repeat that work, to establish whether there'd be any significant change in colonisation of buildings, or the numbers of legionella that were detected. We are never successful in persuading people to give us the money to do that. It was a very expensive survey initially, and wouldn't have been much different, I guess, now, to be quite expensive to undertake. And with the improvement in laboratory techniques, it might have been difficult to interpret some of the results. But my personal feeling is that the proportion of buildings that have legionella in them has probably not changed dramatically, but the actual numbers that are detected will be appreciably lower, and also the frequency of the detection around the building. There's certainly, it's not possible to see any effect on the numbers of cases over the years. No water system, however, that has been shown to be the cause of an outbreak of legionella disease has failed. Sorry, can I start the wrong way around? No water system that's managed and operated following the managerial and technical guidance in LA-8 and the HHG274 and 282 and the HGMS has ever been implicated or shown to be a source of legionella disease. If that's saying anything, I'm not sure. But certainly in every outbreak investigation where we've identified a possible source of legionella disease or definitely identified it, then there've been significant failings in compliance with the law and the guidance. There was concern that the fines in health and safety cases were not reflecting the severity of the offences. And as a consequence, in February 2016, there were new sentencing guidelines produced. And the principal focus of that was to ensure that fines are sufficiently substantial to have a real economic impact, which will bring home to both management and shareholders the need to comply with health and safety legislation. And the fines are based on the company turnover and they may be as much as 10 to 40% of the annual turnover. Potentially huge, international companies, the international turnover would be considered. And we have seen quite a dramatic rise in the last few years and it will continue because this will only apply to cases since 1st of February 2016. So a lot of the cases coming to court now predate that by a long way. But for example, there was this store in, sold a hot tub and infected a number of people. Hot tub was on display, sorry. And the store there was fined a million pounds and there've been several other instances of cases the last year or two where fines have been in the millions. So whether this will have a greater effect on the, or greater effect on the application of the health and safety law remains to be seen. So thank you for listening to me. I hope you've gained some benefit from my discussion. And I'm free now to take any questions. Thank you very much. Yeah, we'll have that committee go ahead and ask you some questions. Start with Chuck Hopp. Yeah, so I've now heard in your presentation that I've heard in the previous several you used the phrase risk assessment. And I wonder if there's any specific guidance as to what that constitutes. What the risk assessment? What is a risk assessment or what constitutes a risk? What constitutes a risk assessment? Well, there's a, it's explained in the HGM document, sorry, in the HSG documents. And there's a standard for risk assessment as BS 8580 which also outlines the process and where, how you go about the process is what you consider. So you consider, as I said before, if the system uses water, what's the temperature of the water or what temperature is it likely to get to? Is there stagnation of the water anywhere? Is the water likely to be aerosolized? So on the hot water system, obviously in the cold water system, there's potential for aerosolization at the outlets, showers, taps and so on. What measures are in place to control the risks existing measures? Whether they're adequate, you'd look at mostly, most of these time these days we're looking at a risk assessment or a system which has already been risk assessed in the past and has already got control measures in place. So in a hotel or a hospital, for example, you'd look at whether the sampling points for measuring temperature and maybe biocide measurements and possibly Legionella or other microbiological sampling were in the appropriate place, whether represented of the highest risk in that system. If not, then they should be recommendations to change them. So it says, I'm not sure that answers your question, but I'd say there's certainly, there's documents several pages long explaining the risk assessment process. No, no. With the water safety plan in a hospital, now you'd look at where the source of water is, whether it's, so if there's a private water supply as well as the public water supply that might imply, have implications, whether there's intermediate storage tanks and so on. So, John, is it the HTML401 document that has the, okay, thank you. And the HSG documents as well. There's a table in the back of the HSG document which lists the things you should be looking at in a risk review or a risk assessment. And I say there's a question. Okay, that's the 274, HSG 274. Yes, yeah. Okay, got it. Steve, Mark. So, just a question about the levels that you've given. We've heard from a couple of different groups about risk levels in terms of detection of Legionella where it's greater than 100 seems to be the threshold for detection as one. But the other is, I think it was greater than 1,000, I think is what it was. Do you have a sense with that data or is that sort of a decision that sort of, from others, is it, where does that, where does the cut-offs come from that you guys didn't use? Well, I should emphasize, I think I didn't say that, testing for Legionella is not essential of hot and cold water systems. The essential things are monitoring temperature or biocide levels where they're applied. And in cooling towers, it will be monitoring your biocide levels, TVC's are monitored as well. General operation of the system, the operation of the biocide dosing. So the microbiological monitoring is only as the final sort of validation. Now the levels, yes, there's a lot of debate about the levels. And in hot and cold water systems, when we've examined those in following outbreaks, we've quite often only seen relatively low numbers. And the important thing is often not so much the actual numbers, but the frequency with which you get isolation. So you're in a hospital and you might find that one area, a couple of wards, have a high frequency of positives. And these will be counts of hundreds or maybe thousands, but rarely above a thousand or 10,000 in hot and cold water systems. So a thousand was considered to be an alarm bell. That's, you wouldn't really want to consistently have those sort of levels in systems because you know that the numbers can actually go up very abruptly overnight to from thousands to tens of thousands or hundreds of thousands. Personally, the highest numbers I've ever seen in a hot and cold water system are in toilet systems in tropical countries, where we've seen hundreds of thousands of lesionella muroffler, the litre. In contrast, in cooling towers, then in, if you look at the data from outbreak investigations on those few occasions when we've actually got to a cooling tower while it's definitely still been infecting people, then the counts have always been above 10 to the five, usually almost with one exception actually, they're always above a million per litre. And so again, the time to go from 10 to the four per litre to a million per litre can be relatively short in nature. So we set a maximum level that would require media action that are relatively low, what might be considered by some to be a relatively low level. In the European guidelines, we did, when we first wrote the European guidelines, which are very much based on the UK guidelines, we did actually relax the action level for cooling towers. In the current guidelines, they've been brought in line with the UK. I'm not sure that really answers your question, but I think it's based on experience, there's not lots of published data, but I'd say a few outbreak investigations. Okay, so we're running a little bit short on time, so we'll take a few more questions, and then we'll wrap it up. Ruth, then we'll go to Michelle, then we'll go to Nick. Okay, thank you, Tom. This is about two questions. Why do you have any codes or laws that address the public water response? The public water supply, I mean, there are drinking water regulations, they do not specify testing for Legionella currently. There are also regulations on the design and construction of hot and cold water systems. They are designed very much to prevent microbial growth and to prevent microbial contamination of systems. So they would in part cover Legionella, but they don't specify Legionella, although they do take Legionella into consideration when you're talking about hot water temperatures. But the current, the European drinking water directive is currently up for revision, and there is a suggestion that Legionella should be included in that. Although we are leaving Europe, well, I'm told we are, we will continue the European drinking water directive as far as I understand. So I guess we'd introduce Legionella testing if that was agreed. I'm not sure personally in a cool climate, whether there's a lot of value in testing main supplies for Legionella. Very, very rarely find them by culture, you can by PCR. But as you get into warmer climates, or certainly if the water temperature increases, then that may well be worth investigating. Again, I've investigated outbreaks in the West Indies where the incoming town supply had thousands of Legionella per litre in it. And my second question is, is there any evidence that use of urine and other testing has increased in the past 10 years? Any evidence that the use of urinary action testing, did you say? Yeah, the clinical, yeah, the clinical use. Yes, I mean, it's been widely used in the UK now for some time, yeah. And in fact, we always, the reference laboratory for decades has had a urinary action in tests which they use as a confirmation. But now, of course, there's bedside tests available which are used widely used. Thank you. Michelle? Yeah, and I have a detailed question for you, John. You covered such wide regulations and all topics. One of the things that I think the UK is very progressive about is the addressing the issue of TMVs or mixing valves and dead ends. I think you have probably the most detailed technical guidance on whether or not to install them. And if you do and they become contaminated, this remembering in your HTMO 401, I think it's the second or third one of that serial one, yeah. Page 59, it shows the importance if it's a TMV and the device is contaminated, what you have to do. And so would you comment in general on where you are in the UK in installing these devices for scalp prevention? Is it still a question of risk balancing or is it like you want to get away from it if you can or are you installing them for scalp protection all over the place still? Right, so there was a big move to install TMVs. There was a big, both in the States and in the UK and probably elsewhere in Europe as well. Of course, there was a big campaign to anti-scolding campaign at one time. And I think this caused too large a swing to the installation of TMVs. And of course, once you install a TMV, you've got no control from that point down on the no temperature control anyway, to enable you to prevent Legionella growing in that. And we did see an increase in the incidence of Legionella in hospitals because of that. The 10 trend now is moving away from installing TMVs wherever possible, but still installing them where there is a risk of, a severe risk of people being installed, so, sorry, being scolded. So in intensive care units, for example, the patients are not going to be washing their hands. There's not really any logical reason for having TMVs there. There will be limited number of showers in those premises as well. So where there's total body immersion, yes, you should have some protection. But where possible, we would discourage fail-safe TMVs. Thank you, John. Nick? Just to follow up on this, would it be possible? Michelle, we're running out of time, so I think we'll have to follow up via email. Okay, thank you. Yeah, yeah, thank you. And Nick? John, in relation to action levels, I was wondering if you had an update from your 2011 publication on the value of QPTR versus culture, and in that paper, as you know, you focused on unofficially contaminated waters. Have you moved on to evaluating that in real scenarios, and what's the uptake for QPTR? Well, we did publish a paper where we looked at naturally contaminated systems. But there's, oh, the HSE has certainly had a group looking at rapid methods. They haven't produced a report yet. That's working in conjunction with Public Health England and the Water Management Society. There hasn't been a big uptake of PCR, to be fair, because of the problems of interpretation. I think people are afraid of using PCR because they know they get lots of positives, and then they don't know how to interpret them. I think we could write guidance which would enable people to interpret them properly. If you've got a system which is under control and you're not getting culture positives, but you're still getting significant PCR positives, then you've got a system which has got Legionella feeding into it from somewhere, and you can trace that source by using PCR, but that's not widely applied at the moment, and there's no real written guidance that's been accepted at the moment in the UK. Having said that, there are more specific PCRs looking for C1 specifically, and also looking for those strains which have a particular pathogenicity market we're interested in, and they have been used in outbreak investigation with success, but not currently being used for routine monitoring. Thank you. Okay, thank you so much. We're going to follow up probably with some emails on some of the reports that you mentioned, and papers, I think we'd be particularly interested in your, if you have documented data on the increase in Legionella cases after the TMV installations in hospitals, before and after. Cases, I think. We have a very low incidence of hospital-acquired cases in the UK. We're less than the European average, significantly less. So it's different, that certainly you've got no statistics on the basis of cases because there aren't sufficient cases to get any significant data. What I was talking about. So you meant occurrence then? When you said that, you meant occurrence in environmental samples? I meant occurrence in environmental samples. That's great. Okay, that would be of interest to us as well. So we'll follow up. We have some other questions in some of these reports, and you threw a lot of information at us, so we're going to look through your emails and get back, or your PowerPoint and get back to you. We really appreciate your time. There's, I've put the web links into the lot of the documents in there so you can get the significant documents. I saw that. Thank you very much. We appreciate it.