A Rare Brain-Eating Amoeba Could Spread Farther North as Freshwater Warms

A summer swim in Lake Claiborne ended tragically for eight-year-old Lillian Smart when she contracted a rare brain infection from Naegleria fowleri, a microscopic amoeba. The Louisiana Department of Health confirmed her death and stated that encountering the amoeba while swimming in the lake was likely the cause. Although common in the environment, infections are extremely rare and invariably fatal.

Naegleria fowleri is a free-living amoeba that thrives in warm freshwater environments like lakes, rivers, and ponds. It feeds on bacteria and other microorganisms. The Centers for Disease Control and Prevention (CDC) warns that the amoeba only poses a threat when water containing it enters a person's nose, leading to a rapid infection that destroys brain tissue.

Symptoms begin with headache, fever, nausea, and vomiting, progressing to severe symptoms like stiff neck, confusion, seizures, and hallucinations. Most patients die within 1 to 18 days after symptoms appear.

The amoeba prefers warm freshwater and can occasionally be found in inadequately chlorinated pools, splash pads, and other recreational facilities. However, swallowing contaminated water does not cause the infection; the water must enter the nose, often during diving, jumping, or swimming underwater activities. Scientists are concerned that climate change could help the amoeba spread to new areas as lakes and rivers warm, increasing opportunities for exposure.

Research suggests the amoeba may be drawn to narrow spaces, possibly triggering its food-seeking behavior in the human nasal cavity. While the overall risk remains extremely low, precautions such as using nose clips, avoiding shallow sediment, and keeping heads above water can reduce the risk further.