A summer swim is supposed to end with nothing more than sunburned shoulders and sand in the car. For one Louisiana family, however, a trip to Lake Claiborne ended in an almost unimaginable tragedy.
Eight-year-old Lillian Smart died after developing a rare brain infection caused by Naegleria fowleri, Louisiana Department of Health officials confirmed. They believe she encountered the organism while swimming in the lake. Although the microscopic amoeba is common in the environment, infections remain exceptionally unusual — but overwhelmingly deadly.
Now, warming temperatures may be changing where those encounters are possible. As climate change heats lakes and rivers and encourages more people to seek relief in the water, scientists are watching whether the heat-loving organism could become more common in areas once considered too cool for it to thrive.
What Is the “Brain-Eating Amoeba”?
Naegleria fowleri is a free-living amoeba, meaning it can survive independently in the environment rather than needing a human or animal host. It naturally inhabits soil and warm freshwater, where it typically feeds on bacteria and other microorganisms.
The Centers for Disease Control and Prevention (CDC) warns that problems begin only when water containing the amoeba is forced into a person’s nose. From there, it can cause primary amebic meningoencephalitis (PAM), a rapidly progressing infection that destroys brain tissue and produces severe swelling.
Explore All OptionsThe first symptoms may resemble more common illnesses and include headache, fever, nausea, and vomiting. As the infection advances, patients can develop a stiff neck, confusion, seizures, hallucinations, and loss of balance. Most people die within 1 to 18 days after symptoms appear.
PAM is extraordinarily rare. According to the Louisiana Department of Health, 180 U.S. cases were reported between 1937 and 2025, and the annual total never exceeded eight. Yet more than 97 percent of known patients have died.
Read More: Deadly Flesh-Eating Bacterium Linked To 5 Deaths in Louisiana as Coastal Cases Rise
Where Naegleria fowleri Lives and Why It Enters the Brain
The amoeba prefers warm freshwater environments, including lakes, rivers, ponds, and hot springs. It has occasionally appeared in inadequately chlorinated pools, splash pads, and other recreational facilities.
Swallowing contaminated water cannot cause PAM. The water must enter the nose, often while someone is diving, jumping, swimming underwater, or stirring up sediment in shallow areas.
Once inside, the amoeba can travel along nerves involved in the sense of smell and pass through tiny openings in the skull to reach the brain. Emerging research discussed in Science suggests this journey may be a biological accident. Naegleria fowleri appears drawn to narrow spaces, possibly because squeezing into crevices helps it find bacteria in pond and lake sediment. The human nasal cavity may inadvertently trigger that same food-seeking behavior.
Could Climate Change Help the Amoeba Spread?
According to a study published in JAMMI, Naegleria fowleri thrives in heat, making a warming climate an increasing concern. Rising air temperatures warm lakes and rivers, while prolonged hot spells can lower water levels and create conditions that favor the amoeba. Cyanobacteria, one of its potential food sources, also flourish in warmer water.
At the same time, hotter weather sends more people into the lakes and rivers, increasing opportunities for exposure. The Bulletin of the Atomic Scientists notes that, historically, most U.S. infections occurred in Southern states, but health officials have now confirmed cases in places such as Minnesota, Iowa, Nebraska, Indiana, and Maryland. Scientists suspect warming waters may be helping shift the organism’s geographic range northward.
The overall risk remains extremely low, but simple precautions can reduce it further. The CDC suggests that swimmers use nose clips when jumping into warm freshwater, avoid disturbing shallow sediment, and keep their heads above water in hot springs. Anyone rinsing their sinuses should use distilled, sterile, or previously boiled water.
This article is not offering medical advice and should be used for informational purposes only.
Read More: FDA Backs the Use of a New Weapon Against Flesh-Eating Screwworm to Treat Infected Pets
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
- This article references information from the Louisiana Department of Health: LDH reports Naegleria fowleri infection in Louisiana resident
- This article references information from the CDC: Naegleria fowleri Infections
- This article references information from Science: ‘Brain-eating amoeba’ appears to love crawling into narrow spaces
- This article references information from a study published in JAMMI: Impact of climate change on amoeba and the bacteria they host
- This article references information from the Bulletin of the Atomic Scientists: Climate change fueled a rise in rare disease outbreaks last year
