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More Microscopic Threats for Fresh-Water Swimmers?



Florida officials are warning summertime swimmers about a rare, brain-eating amoeba that killed a 9-year-old Henrico County boy two years ago.

The one-celled amoeba, called Naegleria fowleri, thrives in warm, stagnant lakes and rivers and can swim through a swimmer's nose into the brain. Almost always, the resulting infection is fatal. Only one person has survived among 128 cases reported to the Centers for Disease Control.

"I haven't heard of alerts in Virginia this summer, it's rare, but it's always a danger," says Rebecca LePrell, director of Environmental Epidemiology at the Virginia Department of Health.

The most recent Virginia fatality occurred Aug. 5, 2011, when Christian Alexander Strickland died of meningitislike ailments. He'd been swimming in several bodies of water in and around the James River as part of a summer fishing camp. "It was impossible to know exactly what water it came from," LePrell says. The previous fatality in Virginia was in 1969.

Naegleria fowleri tends to thrive in hot summer months in Southern states, although two recent cases have been reported in Minnesota's cooler waters. Scientists don't know what conditions make it prevalent enough to be a human threat. Florida tends to have more cases because of its warmer water.

Victims usually inhale the amoeba if they dip their heads below stagnant water while swimming. The amoeba enters the nasal system and can reside in the brain where it destroys tissue. Symptoms usually show up about five days afterward and involve high fever, nausea and vomiting.

Death typically follows, although there are some new drugs being tested, says LePrell, who emphasizes that infections from the amoeba are extremely rare. From the 1930s to the late 1960s, there were only a few in Virginia. Two of them involved swimmers who'd been in two lakes in Chesterfield County. The swimmers died and the lakes later were filled in.

The only prevention is common sense, such as not swimming in murky, stagnant water when there have been alerts. Besides Health Department alerts, there's the online James River Watch (, which updates river conditions, including bacteria warnings, every Friday during summer months. Otherwise, LePrell says, "avoid swimming or don't put your head underwater."

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