A Louisiana man has been hospitalized after contracting an extremely rare and often deadly “brain-eating amoeba” infection after swimming in a popular lake.
The Louisiana Department of Health confirmed Wednesday, Aug. 19, that the patient became infected with Naegleria fowleri after swimming in Lake Claiborne.
Naegleria fowleri is a microscopic organism commonly found in warm freshwater, including lakes, rivers and hot springs.
It can also be found in poorly maintained or inadequately chlorinated swimming pools.
The amoeba can cause a devastating brain infection known as primary amebic meningoencephalitis, or PAM.
The illness is extraordinarily rare, but it is also extremely dangerous.
According to the CDC, only four of the 173 known U.S. patients diagnosed between 1937 and 2025 survived, giving the infection a fatality rate of roughly 97%.
Louisiana has recorded only three confirmed cases since 1937.
Health officials issued an alert to medical providers on Aug. 18 outlining the symptoms doctors should watch for and how suspected cases should be reported.
The amoeba does not usually cause illness if contaminated water is swallowed.
The danger occurs when water containing the organism enters the nose, allowing it to travel toward the brain.
Symptoms generally begin between one and nine days after exposure.
Early warning signs can include severe headache, fever, nausea and vomiting.
As the infection progresses, patients may develop a stiff neck, seizures, confusion, hallucinations and eventually coma.
The disease can move frighteningly fast, with many patients dying within days of symptoms beginning.
Because PAM progresses so rapidly and resembles other forms of meningitis, doctors can have difficulty diagnosing it in time.
Although infections are rare, health officials say there is no practical way to completely eliminate Naegleria fowleri from natural freshwater.
The CDC says the only guaranteed way to avoid infection is to stay out of warm freshwater entirely.
Anyone who does swim in lakes, rivers or other warm freshwater is advised to keep water out of the nose by using nose clips or holding the nose shut when jumping or diving.
Louisiana health officials have not released additional details about the hospitalized patient or their current condition.
