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 two to 15 days of exposure to the amoeba, signs and symptoms of naegleria infection may include:

• A change in the sense of smell or taste
• Fever
• Sudden, severe headache
• Stiff neck
• Sensitivity to light
• Nausea and vomiting
• Confusion
• Loss of balance
• Sleepiness
• Seizures
• Hallucinations

These signs and symptoms can progress rapidly. They typically lead to death within a week.

Naegleria infection is caused by the Naegleria fowleri amoeba, which is commonly found in warm bodies of fresh water around the world, usually during the summer months. 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 tiny 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. And properly cleaned and disinfected swimming pools don't contain the naegleria amoeba.

In the United States, millions of people are exposed to the amoeba that causes naegleria infection each year, but few people get sick from it. From 2007 to 2017, 40 infections were reported.

Some factors that might increase your risk of naegleria infection include:

• Freshwater swimming. Most people who become ill have been swimming in a freshwater lake within the previous two weeks.
• Heat waves. The amoeba thrives in warm or hot water.
• Age. Children and young adults are the most likely age groups to be affected, possibly because they're likely to stay in the water longer and are more active in the water.