Brain-eating amoeba map shows which states have the most cases - USA Today

Naegleria fowleri is making headlines after recent infections linked to warm freshwater exposure. The rare amoeba can cause a severe brain infection that is usually fatal. At least two U.S. cases of primary amebic meningoencephalitis (PAM), caused by Naegleria fowleri, have been reported this summer.

Known as the "brain-eating amoeba," Naegleria fowleri has been in the spotlight after cases linked to contaminated freshwater led to the death of a Louisiana child and severe illness in a North Carolina teenager.

The states with the most reported brain-eating amoeba infections are Texas and Florida, followed by Virginia and California, according to the Centers for Disease Control and Prevention. The CDC's data cover 180 cases with known exposure locations from 1937 to 2025.

Among U.S. states, Texas (40) and Delaware (37) have recorded the most reported Naegleria fowleri infections between 1937 to 2025.

"States with warmer climates have the most PAM cases, but they do occur in northern states as well," the CDC said on its website.

Naegleria fowleri is usually found in warm freshwater lakes, ponds and rivers. People can become infected when contaminated water enters the nose, most often while swimming or diving. Although the disease infects fewer than 10 people a year in the U.S., it continues to draw widespread attention because it progresses quickly and is almost always fatal.

Between 1937 and 2025, there were 180 reported cases of Naegleria fowleri infection in the United States, according to the CDC, with annual totals ranging from zero to eight cases. Cases that occurred between 1937 and 1961 were identified later through a review of past records.