A rare, brain-eating amoeba appears to be spreading further around the US, infecting people in states where it isn’t usually found.
Naegleria fowleri is an amoeba – a single-celled organism that moves via crawling – that lives in freshwater lakes, rivers and hot springs alongside other species of Naegleria. It differs from the other harmless species, however, in that given the chance it will devour your brain.
Fowleri is the only species of naegleria that can infect humans, generally doing so in higher temperatures where it thrives, in bodies of water that are shallow. Infections (though incredibly rare) are picked up typically when people put their heads under the water, with the amoeba traveling up the nose and into the brain, where it causes primary amebic meningoencephalitis (PAM), a disease which is “almost always fatal” at 97 percent, according to the US Centers for Disease Control and Prevention (CDC).
Once in the brain, it begins to destroy brain tissue, producing similar symptoms – such as headache, fever, stiff neck and confusion – to bacterial meningitis. Lack of attention to surroundings, seizures and coma also occur in patients, and the disease usually causes death within five days of the onset of symptoms. Of the 154 people known to have been infected by the amoeba since 1962, only four have survived.
Infections are, thankfully, incredibly rare, with only 31 reported infections over the last decade. However, the areas where the amoeba has been found (and infected people) have been expanding further around the US as temperatures increase.
One study, which looked at recorded cases of PAM as well as temperature information for the area where the infection was picked up, comparing that temperature to historic data for the same area 20 years previously.
“We observed an increase in air temperatures in the 2 weeks before exposures compared with 20-year historic averages,” the team wrote in the report, published in Emerging Infectious Diseases.
“The rise in cases in the Midwest region after 2010 and increases in maximum and median latitudes of PAM case exposures suggest a northward expansion of N. fowleri exposures associated with lakes, ponds, reservoirs, rivers, streams, and outdoor aquatic venues in the United states.”
Official figures for 2022 have not yet been released by the CDC, but as Insider points out, cases do appear to be creeping further north, with a fatal case being picked up in an Iowa lake for the first time. The same was true of Nebraska, where a child died of the disease, which does tend to infect those of 14 years or younger, possibly due to increased exposure to the amoeba through playing in water.
“Our regions are getting warmer,” Douglas County Health Director Dr. Lindsey Huse said in a press conference following the death of a child in Nebraska.
“As things warm up, the water warms up and water levels drop because of drought, you see that this organism is a lot happier and more typically grows in those situations.”
As the climate crisis continues, the creep of the disease further north will likely continue.