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Brain & Nervous System Health Center

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Brain-Eating Amoeba FAQ

Rare, Fatal Amoeba Infection: Your Questions Answered

How Long Do Brain-Eating Amoebas Take to Kill You?

It takes two to 15 days for symptoms to appear after N. fowleri amoebas enter the nose. Death usually occurs three to seven days after symptoms appear. The average time to death is 5.3 days from symptom onset.

Only one U.S. patient survived brain infection with these amoebas. This patient, a 9-year-old California girl, was successfully given anti-amoeba antibiotics and, after a month in the hospital, recovered completely. Worldwide, there have been seven reports of survival.

What Are the First Symptoms Someone Might Have?

Symptoms of PAM are not specific to this disease and resemble those of viral meningitis. Symptoms include headache, fever, stiff neck, loss of appetite, vomiting, altered mental state, seizures, and coma. There may also be hallucinations, drooping eyelids, blurred vision, and loss of the sense of taste.

How Do Amoebas Dissolve Brain Tissue?

One study suggests that N. fowleri amoeba produce two enzymes that dissolve protein.

Are Certain Groups Affected More Than Others?

Over 60% of U.S. cases are in children age 13 or younger. About 80% of cases are in males. It's not at all clear whether children or males are more susceptible to the amoeba, or whether young males are more likely to engage in activities that expose them to the amoeba.

How Can I Protect Myself Against Brain-Eating Amoebas?

It makes sense to avoid swimming underwater, diving, water skiing, and jumping in warm, still waters during the late summer. It also makes sense to wear a nose clip when swimming, boating, or playing in or on warm waters.

However, there's no scientific proof that these measures will prevent N. fowleri infection. Millions of people play in warm waters every summer without having their brains infested by amoebas.

It's a waste of time to put up signs warning that a body of water contains N. fowleri amoebas. There may be more or fewer amoebas depending on the time of year and other factors. More importantly, putting up such signs might imply that bodies of water without signs are safe -- and brain-eating amoebas are relatively common.

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