CDC warning: Don’t use untreated tap water in a neti pot

Another dangerous amoeba linked to nasal rinsing.

NEW YORK — For years, scientists have known people who use neti pots can become 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 published a report that for the first time connects Acanthamoeba infections to neti pots and other nasal rinsing devices.

Officials also renewed their warning that extremely rare, but potentially deadly, consequences can come from flushing nasal passages with common tap water.

“We published this study because we want people to be aware of this risk,” said the CDC’s Dr. Julia Haston, who was lead author of the report published in the journal Emerging Infectious Diseases.

What are neti pots and why do people use them?

Neti pots are one of the better known tools of nasal rinsing, which is one of the most effective ways to clear clogged noses. Their popularity has soared as a treatment for allergies or colds.

Nasal irrigation also has the benefit of keeping the inside of the nose moist, which can help reduce irritation.

Neti pots look like small teapots with long spouts, and usually are made of ceramic or plastic.

Users fill them with a saline solution, then pour the liquid in one nostril. It comes out the other, draining the nasal passage of allergens and other bothersome contaminants.

There also are other methods of rinsing nasal passages, including specially shaped cups and squeezable plastic bottles.

Why you shouldn’t use untreated tap water for nasal rinsing

Tap water in the U.S. is treated to meet safe drinking standards, but low levels of microscopic organisms can still be found in it. These microorganisms are usually

not a problem when people drink or cook with the water because stomach acid kills them. But they pose more of a danger when tap water is used for other purposes — like in humidifiers or for nasal irrigation — because in your nose, these organisms can stay alive in nasal passages and cause serious infections.

More than a decade ago, health officials linked U.S. deaths from a brain-eating amoeba — named Naegleria fowleri — to nasal rinsing. More recently, they started to note nasal rinsing as a common theme in illnesses caused by another microscopic parasite, Acanthamoeba.

Acanthamoeba has 85% fatality rate

Acanthamoeba causes different kinds of illness, with a 85% fatality rate in reported cases, though only 3 of the 10 patients in the new study died.

This amoeba can be found naturally all over the environment — in lakes, rivers, seawater and soil. 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 can cause diseases of the skin and sinuses, and can infect the brain, where it can cause a deadly form of inflammation.

The new study focused on 10 patients who fell ill between 1994 and 2022, three of whom died.

Researchers say they can’t be sure how the patients were infected, but they noted several commonalities: All had weakened immune systems and practiced 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.

Danger for those who use contact lenses

Acanthamoeba also has been connected to non-fatal, but sight-threatening, eye infections, sometimes through contaminated contact lens solution.

Illnesses are still rare

U.S. health officials have identified about 180 infections from the single-cell organism since the first one was diagnosed in 1956.

In the vast majority of cases, researcher don’t know exactly how people became infected. But in reviewing cases in recent decades, CDC researchers increasingly received information that in a number of the cases those infected had done nasal rinsing, Haston said.

“It’s very likely that we’re all exposed to Acanthamoeba all the time,” she said.

False sense of safety

CDC officials, citing a 2021 survey, say about one-third of U.S. adults incorrectly think tap water was free of bacteria and other microorganisms.

Nearly two-thirds said they thought untreated tap water could be safely used for rinsing their sinuses.

In freshwater, beware of brain-eating amoeba

The CDC advises people to assume that the brain-eating amoeba is present in any warm body of freshwater in the United States, regardless of the region. The amoeba has killed in Georgia.

In July, 17-year-old Megan Ebenroth of McDuffie County died from an infection 11 days after swimming with friends in a nearby lake.

The best way to reduce the risk of an infection is to try to avoid getting water up the nose. If you’re in an area where the amoeba could be present, avoid jumping in the water and ideally keep your head above the water.

The amoeba also thrives in sediment at the bottom of bodies of water, so people should avoid stirring up the matter and avoid swimming in stirred-up freshwater.

MOLLY MATALON/NEW YORK TIMES Neti pots look like small teapots with long spouts. Users fill them with a saline solution, then pour the liquid in one nostril.