Brain-Eating Amoeba Strikes in Summer
Six Deaths in 2007 From Amoeba in Warm Fresh Water
How Brain-Eating Amoebas Attack continued...
The amoeba has mouth-shaped structures on its surface called food cups. It's perfectly capable of chewing up brain and blood cells with these food cups, but the blob finds it more efficient to secrete enzymes and proteins that dissolve brain cells so it can suck up the debris with its food cup.
Obviously, this causes a lot of damage. And it happens fast: Victims usually die seven to 10 days after infection, although symptoms may not appear for up to 14 days.
Initial symptoms include headache, fever, nausea, vomiting, and stiff neck. Later symptoms include confusion, inability to pay attention to people and surroundings, loss of balance, seizures, and hallucinations. Death follows the first symptoms by three to seven days.
The disease is technically called primary amoebic meningoencephalitis, or PAM.
"We want to make sure people understand this is a tragic event," Yoder says. "When it happens to a person, particularly if it is a child, we don't want to minimize the tragedy."
At least eight people have survived PAM. All were treated with powerful drugs soon after infection. Unfortunately, most victims aren't treated in time. There are rapid tests for N. fowleri infection, but because the infection is so rare, doctors usually don't suspect a brain-eating amoeba until it's too late.
Brain-Eating Amoeba Not on the Rise
Last summer's six cases were a lot compared to most years. But the CDC says there's no evidence that the brain-eating amoeba is on the rise. There were eight cases in 1980, seven cases in 2002, and six cases in 1978, 1986, and in 1995. Since 1937, there have been only 121 known cases.
So far, there haven't been any cases in 2008. But the CDC warns people either to avoid swimming in warm, fresh water or to wear nose plugs if they do. N. fowleri does not live in salt water or in properly maintained swimming pools, although it has been found in domestic water supplies.
"People should assume there is a risk of swimming in warm, fresh water," Yoder says. "And we think that things people do to minimize entry of water into the nose might provide some reduction of risk, such as using a nose clip. We can't say there is scientific evidence this works, but that is a commonsense approach."