Naegleria (nay-GLEER-e-uh) infection is a rare and usually fatal condition caused by an amoeba commonly found in freshwater lakes, rivers and hot springs. Exposure occurs during swimming or other water sports.
The amoeba — called Naegleria fowleri — travels up the nose to the brain, where it causes severe damage. Most people who have naegleria infection die within a week.
Millions of people are exposed to the amoeba that causes naegleria infection each year, but only a handful of them ever get sick from it. Health officials don't know why some people develop naegleria infection while others don't.
Treatment with certain drugs may be successful if given early enough in a naegleria infection.
Naegleria infection causes a disease called primary amebic meningoencephalitis (muh-ning-go-un-sef-uh-LIE-tis). This disease causes brain inflammation and destruction of brain tissue.
Generally beginning within one to two weeks of exposure to the amoeba, signs and symptoms of naegleria infection may include:
These signs and symptoms can progress rapidly. They typically lead to death within three to seven days.
When to see a doctor
Naegleria infection is caused by Naegleria fowleri amoeba, which is commonly found in warm bodies of fresh water around the world. The amoeba is also sometimes found in soil. The amoeba enters your body through your nose, via contaminated water or dust, and travels to your brain through the nerves that transmit your sense of smell.
Only a very small percentage of the millions of people who are exposed to Naegleria fowleri ever get sick from it. Why some people become infected after exposure and others don't isn't known.
The amoeba isn't spread from person to person or by drinking contaminated water. Properly cleaned and disinfected swimming pools don't contain the naegleria amoeba.
Naegleria infection is extremely rare. In the United States, millions of people are exposed to the amoeba each year but fewer than 10 people a year get sick from it.
Some factors that might increase your risk of naegleria infection include:
While naegleria infection is rare, it's also deadly. The mortality rate is higher than 95 percent.
Preparing for your appointment
If you believe you or your child may have naegleria infection, seek immediate medical attention. You might want to make a list that answers the following questions:
Tests and diagnosis
Spinal tap (lumbar puncture)
Treatments and drugs
Most naegleria infections are difficult to treat successfully. Only a handful of people have survived. The primary treatment for naegleria infection is amphotericin B — usually injected into a vein (intravenously) or into the space around your spinal cord to kill the amoebas.
The Centers for Disease Control and Prevention suggests that the following measures may reduce your risk of naegleria infection:
Last Updated: 2010-03-31
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