At least two people are dead in Louisiana after officials believe "brain-eating amoebas" entered the victims' sinuses through tap water used to fill neti pots.
The 2011 deaths of a 51-year-old woman and 20-year-old man are still under investigation, but now officials are telling neti pot users to heed caution when using the popular devices, KTLA reports.
"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," Louisiana State Epidemiologist Dr. Raoult Ratard said in a statement.
The amoeba, formally known as Naegleria fowleri, destroys brain tissue and kills victims in about one to 12 days, according to a statement by the Louisiana Department of Health and Hospitals. Symptoms include fever, nausea, confusion and loss of balance and are comparable to those of bacterial meningitis.
The amoeba is usually found in freshwater lakes, rivers and ponds and does not normally survive the water-treatment process, Live Science reports. It must enter the body through the nasal cavity; it cannot be ingested through drinking water.
While it's uncommon for tap water to contain the deadly amoeba, it may house harmful bacteria, such as e-coli, ABC 4 News reports.
Cases of Naegleria fowleri infections are uncommon.
"In the 10 years from 2001 to 2010, 32 infections were reported in the U.S.," according to the Louisiana Department of Health and Hospitals. "Of those cases, 30 people were infected by contaminated recreational water and two people were infected by water from a geothermal drinking water supply."
Neti pots are considered safe as long as people take the proper precautions before using them, Dr. Saurabh Shah, an ear nose and throat specialist, told ABC 4 News.
Correction: A previous version of this article contained a sentence that incorrectly referred to Naegleria fowleri as a bacteria. Naegleria fowleri is an amoeba.