Brain-Eating Amoeba

A brain-eating amoeba infection occurs when the Naegleria fowleri (N. fowleri) amoeba gets into your brain and rapidly destroys tissue. Amoebas are single-celled organisms that sometimes infect people. Naegleria fowleri infections can lead to primary amoebic meningoencephalitis (PAM), severe brain inflammation that’s almost always fatal.

Naegleria fowleri lives throughout the world in warm and shallow bodies of fresh water, like lakes, rivers and hot springs. It also lives in soil.

Getting infected is very rare. The most common way it happens is when water containing N. fowleri goes up your nose. From there, the amoeba travels to your brain. This usually happens when you’re swimming, diving or water skiing in affected water.

Symptoms of a brain-eating amoeba infection

It takes about two to 15 days after the amoeba enters your body for symptoms to develop. The symptoms then come on suddenly.

Early signs and symptoms of PAM include:

• High fever
• Very painful headache
• Nausea and vomiting

Later symptoms include:

• Stiff neck
• Extreme sensitivity to light (photophobia)
• Confusion
• Imbalance
• Hallucinations
• Coma

If you develop symptoms of fever or headache after going into warm freshwater, tell a healthcare provider right away.

Naegleria fowleri infection causes

The infection occurs when the Naegleria fowleri amoeba gets into your brain through your nose. It can enter your body if you inhale infected water. Usually, the amoeba lives in warm freshwater, including hot springs (geothermal water).

Other, rarer ways to become infected include:

• Inhaling infected dust
• Using infected tap water to rinse your sinuses or cleanse your nasal passages
• Spending time in splash pads and surf parks that don’t use enough chlorine

Swallowing infected water doesn’t cause it. And it doesn’t spread from person to person.

How doctors diagnose it

If a healthcare provider thinks you might have been infected by an N. fowleri amoeba, they’ll do a spinal tap. It checks your cerebrospinal fluid for the organism.

Your provider may also recommend a brain biopsy. During this procedure, they’ll take a tissue sample and examine it under a microscope to look for the amoeba.

How is a Naegleria fowleri infection treated?

The go-to treatment for primary amoebic meningoencephalitis, or infection with brain-eating amoeba, is a combination of the following medications:

• Amphotericin B
• Miltefosine
• Azoles such as fluconazole and voriconazole
• Rifampin

The best results, which were in two children who recovered completely, came from early diagnosis and treatment with the recommended drugs. Providers also cooled the children’s bodies to below-normal temperature to treat brain swelling.

Researchers are looking into other treatment options. Your care team may try experimental treatments if you agree.

What can I expect if I have a brain-eating amoeba?

The outlook for someone who is infected with Naegleria fowleri is very poor. The fatality rate is higher than 97% even with treatment.

Coma followed by death usually happens in a week or 10 days after symptoms begin.

Can this be prevented?

To reduce your risk of getting a brain-eating amoeba infection, follow these steps:

• Don’t go into water at all if Naegleria fowleri is known or is likely to be present.
• Always use nose plugs or clips while swimming, wading or doing watersports in warm freshwater locations, especially still waters.
• Always keep your head above water in hot springs.
• Don’t use tap water for a neti pot or any other device that cleans your nasal passages. Only use distilled or sterilized water.
• If you must use tap water to clear your nasal passages, make sure that you boil it for one minute and then let it cool. If you live somewhere that’s 6,500 feet above sea level, boil the water for three minutes and then let it cool.
• Use filters to remove germs from water that are labeled “NSF 53,” “NSF 58” or “absolute pore size of 1 micron or smaller.”
• Use liquid or tablet chlorine bleach to disinfect your water for cleaning your nose and sinuses. Disinfecting water for nasal use requires a different amount of bleach than disinfecting water for drinking.