 grew up in deep East Texas. Those of you who have never visited Texas might be thinking of tumbleweeds, cacti, and rednecks. You'd be right on one of those three. Northeast Texas, at least in parts, is a swamp. The part just adjacent to Louisiana is everything you expect of a semi-tropical swamp. Hot, humid, and lots of little blackwater lakes. I used to love to swim, dive, and fish in the local lakes. I tell you this to give you background on why I will never, not ever, absolutely never, ever, ever go back into a warm freshwater lake ever again. It used to be one of my favorite activities, but one thing ruined it. Pam. Pam is not an ex-girlfriend or creepy old nudist lady. It's not a person at all. It's primary amoebic meningoencephalitis, P-A-M. It's a very, very rare health threat. Only 32 proven cases in the last decade, about a hundred in the history of the US. 28 of those cases were from swimming in freshwater ponds, lakes, or pools. Two were from a drinking water supply that was heated geothermally, and two of those infections were the result of watching Oprah. Okay, not watching Oprah, exactly, but those two cases were the result of using neti pots, and the neti pot craze certainly started on Oprah's talk show. I'm going to talk about Pam, and I'm going to talk about neti pots, then I'm going to summarize what the real risk connection is between those two things. One, a little more about Pam. It's horrible. We have no tests to diagnose it. We have no drugs that we know work on it. If you contract Pam, you have only a 2% chance of surviving. It's a death sentence, and it will be a painful, lingering death. I have studied Ebola and LASA. I have been in biosafety level four facilities, and this thing scares me irrationally. The causative agent in Pam, typically an amoeba called nigleria fowleri, needs warm freshwater to thrive and grow. That's why cold water lakes are relatively safe. It's also no threat for drinking water as stomach acids destroy it quickly. It's only route to penetrate your defenses is in the nose. Since prior to humans swimming in freshwater for recreation, and of course since Oprah suggested pouring warm water into your nose, the disease has increased in prevalence. Hey, bonus depression, thanks to a warming trend, lakes as far north as Ohio are likely to be infectious during the summer months, signaling a general trend of expansion for Pam. If you wonder where the stuff was when you were a kid jumping off a tire swing into a local watering hole, the answer is that it was much further south in the tropics. Thanks, global warming. The amoebic agent goes through multiple stages in its life cycle, including a cyst stage where it can remain dormant and protected from its environment for years. Yes, that's right. It can survive cold, starvation, toxic chemicals and desiccation and still pop up and eat your brain. To our neti pots effective. Actually, yes, a little running warm isotonic salt water does help to moisturize and wash out the crud from the little hairs in your nasal sinus. It's not rocket science. The warmth, moisture and flushing effect can be pretty soothing. That's why it's been used medically for decades following sinus surgery to wash out wounds. The neti pot is a bit of silliness invoking the ancient wisdom fallacy that anything that's been practiced for thousands of years must be effective. Anyone who thinks that doesn't know humans very well. There have been multiple papers studying the effectiveness of nasal irrigation, whether the irrigation is done with a plastic squirt bottle or vitrified ceramic neti pot. It does reduce swelling and pressure. A Cochrane database review of all available literature found that there is evidence that saline is beneficial in the treatment of the symptoms of chronic rhinocyanositis when used as the sole modality of treatment. Evidence also exists in favor of saline as a treatment adjunct. No superiority was seen when saline was compared against a reflexology placebo. Saline is not as effective as an intra nasal steroid. There are also Cochrane reviews of saline nasal irrigation for acute upper respiratory tract infections, but the results there are not encouraging. The side effects are nasal soreness can include nose bleed and headache. If you want to avoid the side effect of death by brain eating amoeba, you should never never use tap water. You should boil then cool or otherwise sterilize any water that goes in your nose. The neti pot or other containers should be thoroughly cleaned after each use and allowed to air dry. In short, properly use the neti pot is about as effective as any other folk remedy at making you feel better, but it doesn't address the root cause of nasal troubles. It's not as effective as a steroid, but the side effects are pretty mild. Three now to summarize the real risk of PAM from nasal irrigation. The absolute risk is fairly easy to calculate as long as we can make up some numbers. Two reported cases assuming that's pretty good coverage. I have no reliable numbers on how many people use neti pots, but let's use a plausible number of 1 million in the US. Given our wild guess is the incidence of PAM is two cases in 1 million exposed or 0.2 cases per 100,000 in 10 years. The per year number moves one more decimal 0.02 cases per 100,000. The incidence of lightning strike is about 0.1 cases per 100,000 in the general US population of about 300 million. That means that the risk of PAM is about equivalent to the risk of any given person getting hit by lightning. Oh, that's not proper epidemiology, but the absolute risk is pretty small. That's my point. Of course, if the water is pre filtered, boiled and cooled, the pot cleaned and air dried after every use, the risk is essentially zero or at least has never been measured to be more than zero. Every case so far has been the result of using tap water. So, my final verdict on neti pots. Well, even a stock clock is right twice a day. Oprah gets a pass on this one. Neti pots are relatively safe, so long as you take some very basic precautions and never, never, never use tap water in them. If PAM scares you as much as it scares me, you can be excused from a little irrationality. But if you're looking for a realistic assessment of risk, you are thousands of times more likely to die from slipping in the shower or falling off a ladder. Why am I so against swimming in warm water lakes of my native Texas? We established that the absolute risk is really quite low. Even though the risks are higher for getting PAM from swimming, the relative risk ratio that is the comparison of the exposed and unexposed populations would be really quite high. The difference in disease rates among non-lake swimmers and non-neti pot users is relatively large. Sitting here at my computer, there is almost no chance that a brain eating amoeba will be lurking in the shadows preparing to pounce upon and devour my delicious head meats. The moment I dip a nostril in Caddo Lake, however, PAM is just waiting for me. Possibly. Maybe. Probably not, but I'll be darned if she's going to get my cerebrum. Thanks for watching.