The deadly infection has been historically rare, but as climate change heats up waters and worsens flooding, research shows cases could become more common.
MISSOURI, USA — A Missouri resident is in intensive care after officials confirmed they had contracted a rare and deadly infection after swimming at the Lake of the Ozarks.
Missouri Department of Health and Senior Services confirmed the swimmer was infected with Naegleria fowleri, commonly known as a brain-eating amoeba. The amoeba can cause a deadly infection of the brain called primary amebic meningoencephalitis, or PAM.
The Centers for Disease Control reports that the amoeba often causes death in people between one to 18 days after infection, usually five days after the start of symptoms. Early stage infection symptoms include typical meningitis symptoms like fever, headache, and stiff neck. Anyone experiencing these symptoms after swimming in warm fresh water are advised to seek healthcare immediately.
“Symptoms get worse pretty rapidly and most people actually pass away within about five days,” Missouri Department of Health and Senior Services Epidemiologist Nathan Koffarnus said.
The amoeba is naturally present in warm freshwater and is often found during the summer months, but human infection has historically been extremely rare, health department officials said. There have only been 167 reported cases of the infection in the United States between 1962-2024.
“I definitely understand why there is concern because we honestly don’t have very good treatment that can result in success,” said Dr. Farrin Manian, the chairman of the Department of Medicine at Mercy.
The last time a Naegleria fowleri infection was confirmed in Missouri was in 2022. The only other confirmed case in the state was in 1987.
“The source of the patient’s exposure is currently being investigated by public health officials,” officials said. “While not confirmed, preliminary information implies the patient may have been water skiing at the Lake of the Ozarks days prior to becoming ill. Recreational water users should assume that Naegleria fowleri is present in warm freshwater across the United States; however, infection remains very rare.”
No other suspected cases of PAM are being investigated in Missouri at this time, according to the department. 5 On Your Side reached out to the Centers for Disease Control for additional comment, but it deferred to Missouri health officials.
Although Naegleria fowleri infections have historically been rare, recent research warns that warming temperatures and increasingly frequent floods caused by human-induced climate change are making infections occur more often.
The amoeba thrives in temperatures between 80 and 115 degrees, which is outside the livable range of competing microorganisms, according to research published in 2023. Lakes and rivers are becoming hotter due to climate change, and stronger storms are increasing the amount of organic matter that ends up in the waterways through flooding, creating the perfect storm for Naegleria fowleri populations to spike.