By MIKE STOBBE (AP Medical Writer)
For a long time, scientists have known that people who use neti pots can get infected with a brain-eating amoeba if they use the wrong kind of water. On Wednesday, researchers linked a second kind of deadly amoeba to nasal rinsing.
The Centers for Disease Control and Prevention released a report that, for the first time, connects Acanthamoeba infections to neti pots and other nasal rinsing devices.
Officials also reiterated their warning that although extremely rare, flushing nasal passages with ordinary tap water can have potentially deadly consequences.
“We published this study because we want people to be aware of this risk,” said the CDC’s Dr. Julia Haston.
Neti pots are one of the more well-known instruments for nasal rinsing. They resemble small teapots with long spouts, and are typically made of ceramic or plastic.
Users fill them with a saline solution, then pour the liquid into one nostril. It comes out the other side, clearing the nasal passage of allergens and other irritating contaminants.
The use of neti pots in the U.S. has increased significantly over the past few decades, partly due to the growing prevalence of allergies and other respiratory diseases, according to market researchers.
There are also other ways to rinse nasal passages, including specially shaped cups and squeezable plastic bottles.
Tap water in the U.S. is treated to meet safe drinking standards, but small amounts of microscopic organisms can still be present in it. This is usually not a problem when people drink or cook with the water, but it can be more of a risk when tap water is used for other purposes—like in humidifiers or for nasal irrigation.
CDC officials, citing a 2021 survey, say about one-third of U.S. adults mistakenly believe tap water is free of bacteria and other microorganisms. Nearly two-thirds think tap water can be safely used for rinsing their sinuses.
The CDC recommends using boiled, sterile, or distilled water.
If tap water is used, it must be boiled for at least one minute—or three minutes at higher elevations—before it is cooled and used, officials say.
More than ten years ago, health officials connected U.S. deaths from a brain-eating amoeba—named Naegleria fowleri—to nasal rinsing. More recently, they began to notice nasal rinsing as a common factor in illnesses caused by another microscopic parasite, Acanthamoeba.
Acanthamoeba causes different types of illness but is still hazardous, with an 85% fatality rate in reported cases.
“These infections are very serious and even life-threatening,” said Haston, who was the lead author of the report published in the journal Emerging Infectious Diseases.
The new study focused on 10 patients who became ill between 1994 and 2022, three of whom died. Researchers say they can’t be certain how the patients were infected, but they noted several similarities: All had weakened immune systems and engaged in nasal rinsing.
Seven patients reported nasal rinsing for relief of chronic sinus infections, and at least two of them used neti pots. Two other patients did nasal rinsing as part of a cleansing ritual that is part of Indian tradition.
This tiny living thing can be naturally found everywhere in the environment — in lakes, rivers, seawater and soil.
It can lead to illnesses of the skin and sinuses, and can invade the brain, where it can cause a deadly type of inflammation. The microorganism also has been linked to non-deadly, but sight-threatening, eye infections, sometimes through contaminated contact lens solution.
U.S. health officials have identified approximately 180 infections from the single-cell organism since the first one was diagnosed in 1956.
In most cases, researchers don’t know exactly how people became infected. But in reviewing cases in recent decades, CDC researchers increasingly received information that a number of the cases had done nasal rinsing, Haston said.
Research also has indicated it’s common in tap water. A study done in Ohio in the 1990s found more than half of tap water samples studied contained the amoeba and similar microorganisms.
“It’s very likely that we’re all exposed to Acanthamoeba all the time,” she said.
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The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Science and Educational Media Group. The AP is solely responsible for all content.
