The Louisiana Department of Health and Hospitals is warning people against the improper use of neti pots, following the deaths of two people who were infected with Naegleria fowleri — the so-called “brain-eating amoeba” — after using tap water to irrigate their sinuses.
A 53-year-old woman from De Soto Parish and a 20-year-old man from St. Bernard Parish both died after using contaminated water in their neti pots, a popular home remedy that looks like a genie’s lamp and is used for flushing out mucus from the nose and sinuses.
“If you are irrigating, flushing or rinsing your sinuses, for example, by using a neti pot, use distilled, sterile or previously boiled water to make up the irrigation solution,” said Louisiana State Epidemiologist, Dr. Raoult Ratard.
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Tap water is safe for drinking, but not for irrigating your nose, Ratard said. It’s also important to rinse the neti pot after each use and leave it open to air dry.
Typically, Naegleria fowleri infection occurs when people go swimming or diving in warm freshwater lakes and rivers, particularly in summer in the southern U.S. Last summer, at least three other people died from Naegleria fowleri infection in Florida, Virginia and Kansas.
The amoeba enters through the nose, travels to the brain and starts eating neurons. It sounds scary — and it is — but it’s also exceedingly rare. In the 10 years from 2001 to 2010, only 32 infections were reported in the U.S., despite millions of people swimming in lakes and rivers. Of those infected, 30 people were infected by recreational water sources, and two were infected by water from hot springs.
In even rarer cases, according to the Centers for Disease Control and Prevention (CDC), people can get infected with Naegleria fowleri when contaminated water from other sources, like inadequately chlorinated pools or tap water heated to less than 116.6 degrees F, gets into the nose.
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Although uncommon, when Naegleria fowleri infection occurs, it’s nearly always deadly. It’s hard to diagnose and hard to treat. The amoeba causes primary amebic meningoencephalitis (PAM), which destroys brain tissue. In its early stages, symptoms of PAM look like bacterial meningitis. The first symptoms start 1 to 7 days after infection, with headache, fever, nausea, vomiting and stiff neck. Later symptoms include confusion, lack of attention to people and surroundings, loss of balance, seizures and hallucinations. The disease progresses rapidly after the onset of symptoms, usually causing death within 1 to 12 days.
For more on Naegleria fowleri, check out the CDC’s page here. And if you’re using a neti pot for sinus problems, make sure you use sterile, distilled or boiled water — cool it before flowing it through your nose, obviously.
Sora Song is the editor of TIME Healthland. Find her on Twitter at @sora_song. You can also continue the discussion on TIME Healthland’s Facebook page and on Twitter at @TIMEHealthland.