Brain-eating amoeba found in popular recreation areas

The Naegleria fowleri amoeba can cause a rare but fatal brain infection that progresses quickly and can’t be cured. And it has been found in several recreational locations in the U.S., with the number of cases likely to increase as global temperatures rise.

Unwelcome inhabitant

Scientists tested 185 water samples from 40 recreational waterways across five National Park Service sites. N. fowleri was found in 34% of the samples, according to a study published in the journal ACS ES&T Water. The amoeba was “detected in well-known and previously untested hot springs, including sites with high recreational use,” including Yellowstone National Park, Grand Teton National Park and Lake Mead National Recreation Area, said the study.

The single-celled organism is “very widespread” and “not just national park hot springs,” said study author Brent Peyton, a professor at Montana State University, to Outside. The amoeba “thrives in soil and warm freshwater lakes, rivers, ponds and hot springs all over the globe,” said USA Today. It flourishes in “warm pools up to 115 degrees Fahrenheit,” as “water across western national parks is getting warmer,” said Outside.

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Brain infection most often occurs when someone “goes swimming or diving in a lake, river or other fresh water during summer months” and the amoeba enters the nasal cavity, said the CDC. A few infections have occurred when people “used tap water that contained Naegleria fowleri to rinse their sinuses or cleanse their nasal passages.” However, you cannot get an N. fowleri infection from “swallowing water containing the amoeba,” get it “from someone else” or “pass it on to others.”

The infection, primary amoebic meningoencephalitis (PAM), advances quickly, destroying brain tissue and causing massive cerebral swelling, with most people dying “within one to 18 days after symptoms begin,” said USA Today. The amoeba can “infect their brain with a fatality rate of 98%.”

PAM symptoms include “headache, fever, nausea and vomiting,” said the CDC. And as the disease progresses, it can cause a “stiff neck, confusion, lack of attention to people and surroundings, loss of balance, and hallucinations.”

Domain expansion

There's “no need to be alarmed,” said study author Brent Peyton, a professor at Montana State University, to Outside. Infection can be “prevented by keeping water out of one’s nose.” Experts suggest people “hold their nose or wear a nose clip if they are jumping or diving into fresh water,” keep their "head above water in hot springs,” and avoid splashing around in shallow water, as the amoeba is more likely to be found there, said Fast Company.

Other bodies of water may also become more hospitable to N. fowleri due to warming temperatures. The findings “indicate that N. fowleri is present in thermally impacted areas across the western United States,” said the study. The amoeba’s presence underscores the “use of enhanced monitoring, public awareness and risk management strategies in thermally influenced recreational waters.”