Missouri swimmer dies of rare brain-eating amoeba

A Missouri resident who became infected with a rare, brain-eating amoeba possibly while swimming in an Iowa lake has died, health officials said.

The Missouri Department of Health and Senior Services reported on July 7 that it had a confirmed case of Naegleria fowleri, a rare but often deadly infection.

The resident may have been exposed to the amoeba -- commonly found in warm freshwater like lakes and rivers -- while swimming at the Lake of Three Fires in Taylor County, Iowa, health officials said.

The Iowa Department of Health and Human Services announced on July 8 that the beach was temporarily closed to swimming as a "precautionary response to a confirmed infection of Naegleria fowleri in a Missouri resident with recent potential exposure while swimming at the beach."

The Iowa Department of Health and Human Services said it was conducting testing in conjunction with the Centers for Disease Control and Prevention to confirm the presence of Naegleria fowleri in the lake.

The Missouri patient was being treated in an intensive care unit for primary amebic meningoencephalitis, a life-threatening infection of the brain caused by the amoeba, health officials said.

The patient has since died due to the infection, the Missouri Department of Health and Senior Services said.

"While the occurrence of Naegleria fowleri infection is extremely rare, once infected it is usually fatal," Lisa Cox, a spokesperson for the health department, said in a statement to ABC News Saturday. "Because these cases are so incredibly rare and out of respect for the family, we do not intend to release additional information about the patient which could lead to the person's identification."

Out of 154 known cases of primary amebic meningoencephalitis reported in the U.S. from 1962 to 2021, only four people have survived, according to the CDC.

The infection was Missouri's first case of primary amebic meningoencephalitis since 1987. No additional suspected cases are being investigated in the state, the health department said.

"These situations are extremely rare in the United States and in Missouri specifically, but it's important for people to know that the infection is a possibility so they can seek medical care in a timely manner if related symptoms present," Dr. George Turabelidze, Missouri's state epidemiologist, said in a statement.

People can become infected by Naegleria fowleri when water containing the amoeba enters the body through their nose. It can then travel to their brain and destroy the brain tissue.

Symptoms of primary amebic meningoencephalitis include severe headache, fever, nausea, vomiting, stiff neck and seizures.

People can try to reduce their risk of becoming infected by Naegleria fowleri by limiting the amount of water that goes up their nose while in bodies of warm freshwater and by avoiding water recreation in warm freshwater during periods of high water temperature.

From 2012 to 2021, 31 infections were reported in the U.S., with most people infected by recreational water, according to the CDC.

In a recent high-profile case, a 3-year-old boy died from primary amebic meningoencephalitis in September 2021 after contracting Naegleria fowleri at a Texas splash pad. City officials subsequently found there had been lapses in water-quality testing at several parks.

Infections with Naegleria fowleri mainly occur during the summer months and in southern states, though can occur in more northern states, the CDC said.

"Recreational water users should assume that Naegleria fowleri is present in warm freshwater across the United States," the CDC said while noting that infection remains rare.

Experts warn that climate change may contribute to life-threatening risks for swimmers, as waterborne pathogens like Naegleria fowleri can thrive and multiply faster in increasingly warming waters.