This is not a supermarket tabloid story…I assure you it’s genuine. Five people in four states were killed in the US in 2011 by a brain-eating amoeba—two of them because ordinary tap water got into their noses. Yes, ordinary tap water. Now, the reason this particular tap water killed these people was that they had used it to clean out their sinuses using something called a neti pot. You might be familiar with neti pots because I have written about them before—but never as potentially fatal! So to learn more about this bizarre danger, I called Raoult Ratard, MD, state epidemiologist at the Louisiana Office of Public Health, because he has spent many years studying how various types of infections affect different populations all over the US.
WHAT’S REALLY IN YOUR WATER?
First of all, in case you are thinking, What’s a neti pot?, it is a small vessel, usually ceramic or plastic, that looks like a small teapot with an elongated spout. A user fills the neti pot with lukewarm water, tilts his head sideways and tips the spout into the upper nostril. Water runs into that nostril and then, by simple gravity, out the lower nostril. Neti pots originated in ancient India, and today, many holistic practitioners and even some MDs around the world recommend their use for cleaning out nasal passages and easing sinus congestion or dryness. The directions that come with neti pots usually contain a warning to use sterile or distilled water, but many consumers use more convenient tap water.
The problem is that most tap water in the world has an assortment of amoebae (one-celled organisms) in it. Yes, you read that right, though you may wish you hadn’t. Amoebae can survive normal public water treatment and set up a colony (called a biofilm) around the system’s filters or in home plumbing.
Amoebae (such as Naegleria fowleri, which killed the neti pot users mentioned earlier) are regularly found in tap water. They’re innocuous when they’re swallowed because they can’t survive stomach acid and a trip through the human digestive system. And if you bathe in water that contains them, they won’t harm you either. But they are potentially dangerous—and very much so—to neti pot users when they go deep into nasal passages.
Dr. Ratard explained that there is a paper-thin bone at the top of the nasal cavity with holes through which the smelling (olfactory) nerves pass to connect with the brain. An amoeba can travel up those nerves and into the brain, which the amoeba then begins to consume. Symptoms (headache, nausea, vomiting, confusion) appear within one to seven days after infection, and the patient almost always dies one to 12 days after onset of symptoms.
The thought of brain-eating amoebae simply floating around in my tap water sure does give me the heebie-jeebies. So I asked Dr. Ratard how we can protect ourselves.
CAUTIONS FOR NETI POT USERS
- Use only sterile or distilled water in your neti pot. Dr. Ratard says that if you want to use tap water, first boil it for one to three minutes to kill any amoebae. Then, of course, let the water cool before putting it in the neti pot and using it.
- Clean your neti pot thoroughly by washing it with soap and hot water or by running it through the ultra-high temperature water of a dishwasher to kill any amoebae. Let it air-dry thoroughly between uses, because amoebae can’t survive long on a dry surface.
There’s also a chance of an amoeba infecting your brain while you swim. Millions of people all over the US swim in warm fresh water (over 77°) that contains amoebae—such as lakes, ponds, rivers and unchlorinated pools (chlorine at high concentrations kills amoebae)—without getting infected. But a very few do get infected.
Unfortunately, said Dr. Ratard, there are no key warning signs that a body of water has amoebae in it. It doesn’t look, feel or smell any different. Some towns test certain bodies of water, but Dr. Ratard told me that the tests are not very reliable because the amount of amoebae in the water varies day to day and it can take weeks for the test results to be processed. So if you find yourself in a warm body of water that’s not chlorinated, try to keep your head above water and don’t dive in. If you do go under, hold your nose or wear a nose clip and try not to snort any water up your nose.
So, yes, this is creepy news, but it’s important to keep it in perspective. The odds of an amoeba getting all the way up in your nasal cavity and then infecting your brain still are incredibly small. The CDC offers this perspective—in the 10 years from 1996 to 2005, 36,000 Americans drowned, but only 32 died of brain infections from amoebae.