In 2007, six people from southern states died from a rare brain infection that can occur after swimming in warm lakes and rivers, according to findings released Thursday in the Morbidity and Mortality Weekly Report
Primary amebic meningoencephalitis (PAM) is a rare, but nearly always fatal disease caused by the amoeba Naegleria fowleri, investigators from the CDC and the states where the infections occurred note. The microbe enters the brain through the nose and the infection causes various symptoms, including headache, neck stiffness, nausea, and vomiting.
Although Naegleria folwleri is a common inhabitant of warm lakes and rivers, just 121 cases of PAM have been reported over the last 71 years.
Of the six cases described in the current report, one occurred in Arizona, three in Florida, and two in Texas. Five of the cases involved a male child or adolescent and the sixth involved a young man. A few days before coming to the hospital, all six patients had participated in activities involving exposure to warm freshwater.
Despite antibiotic therapy and other treatments, all of the patients died, usually within a day or two of hospital admission, the report indicates.
In reviewing previously reported cases, the researchers found that nearly all involved individuals who had been swimming in warm freshwater in a southern state. Nearly three quarters of the patients were male and the typical age was 12 years. Eighty-five percent of the cases occurred during July, August or September.
"The only certain way to prevent Naegleria fowleri infection is to refrain from water-related activities," the authors conclude. "However, although supporting data are absent, risk for infection might be reduced by measures that minimize water entering the nose (such as nose plugs) when using warm freshwater lakes or rivers in southern tier states."