Home Medical profession What freshwater swimmers should know about the amoeba Naegleria fowleri

What freshwater swimmers should know about the amoeba Naegleria fowleri


A rare, but often deadly, hazard lurks in freshwater ponds, rivers and lakes across the United States ⁠ — and experts say recreational swimmers need to be aware.

In early July, Iowa officials announced the closure of a beach at its Lake of Three Fires state park after a Missouri resident contracted Naegleria fowleri, also known as the “eating amoeba of brain”, after having swum there at the end of June.

The person died of a rare and usually fatal brain disease caused by Naegleria fowleri called primary amoebic meningoencephalitis, or PAM, Lisa Cox, spokeswoman for the Missouri Department of Health and Senior Services, said at USA TODAY.

Specific diagnostic tests for the amoeba are available in only a few laboratories in the United States, and infections are so rare and difficult to detect initially that 75% of diagnoses are made after death, according to the Centers for Disease Control and Prevention. Amoeba infects a person through water through the nose.

After one person in California survived in 1978, reported cases were fatal for 35 years until three children beat the infection in the past decade, according to the CDC:

Here’s what you need to know about Naegleria fowleri.

What is Naegleria fowleri?

Naegleria fowleri is the only Naegleria species that infects humans and has a 97% mortality rate, according to the CDC. Amoeba is usually found in soil and warm or warm freshwater, such as lakes, rivers, ponds, and hot springs. It can also live in poorly chlorinated water heaters or swimming pools, according to the CDC.

The amoeba thrives in temperatures as high as 114.4 degrees Fahrenheit, said Paul Rega, retired assistant professor at the University of Toledo in public health, disease prevention and emergency medicine.

“Naegleria fowleri is ubiquitous; it is found in both fresh waters and soils on six of the seven continents,” he said. Rega added that people can also get it from contaminated water on water slides or during artificial white-water rafting and water skiing.

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The amoeba is not found in salt water, according to the CDC. “Salt dehydrates cells, so it’s like a natural disinfection system,” said Christopher A. Rice, associate scientist and director of the Center for Drug Discovery at the University of Georgia College of Pharmacy.

What is the impact of climate change on the spread of Naegleria fowleri?

Naegleria fowleri is often found in freshwater in southern states like Texas and Florida, two states where the CDC reported 76 cases of MPA between 1962 and 2021. These cases make up the bulk of reported cases of Naegleria fowleri in the states. -United.

With 10 cases over a period of nearly 50 years, California had the third highest frequency of reported cases. CDC data shows that during this period, 154 cases of amoebas were reported. All but four were fatal.

Recent cases have been reported as far north as Minnesota and Iowa as climate change increases freshwater temperatures in northern states, Rega research shows.

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“The incidence will increase not only because more people could be exposed, but also because it will not be diagnosed in a timely manner due to the naivety of the health profession in many parts of the country,” a- he added.

How does Naegleria fowleri kill quickly?

Naegleria fowleri can make its own nutrients, but continues to forage in soil or water to feed on bacteria, fungi, and other organisms. That’s how problems can arise for freshwater swimmers, Rice said.

If contaminated water goes up a person’s nose, the organism migrates to the brain, leading to infection with primary amoebic meningoencephalitis, he said. Rice added that misdiagnosis and mistreatment are the reason so few people survive MPA.

This image provided by the Centers for Disease Control and Prevention shows the amoeba Naegleria fowleri in one of three stages of development.

Naegleria fowleri is often misdiagnosed as bacterial or viral meningitis, Rice said. The diseases share early-stage PAM symptoms like vomiting, fever, and nausea. The amoeba can kill within days.

“Patients succumbed between one day after symptoms and between 13 and 15 days after symptoms,” Rice said.

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It can grow and divide in 10 hours, and therapeutics suggested by the CDC can take between three and five days after diagnosis to work, Rice said. He explained that the amoeba does not cause problems when swallowed, as stomach acid kills it.

How to avoid brain-eating amoeba infection?

The key to avoidance is keeping fresh water out of your nose, experts say. The CDC recommends assuming that any warm freshwater body in the United States contains Naegleria fowleri.

“Maybe wading through the water rather than splashing around and getting water in your nose,” Rice said. If jumping, holding the nose can help, he added.

Swimmers should avoid immersing their heads under fresh water when swimming or diving, Rega said.

“Good nasal plugs would also prevent the amoeba from entering the nose,” he said.