Brainy Fact: Brain-eating Amoeba Infection

Naegleria fowleri

Naegleria fowleri, one of the species in the genus Naegleria and the only one known to cause disease in humans. It is known to proliferate in warm freshwater conditions.

The infection caused by this amoeba was first documented in Australia in 1965. N. fowleri have motile trophozoites that destroy brain tissue with which they come into contact. It only affects the brain tissue as it migrates towards the anterior cerebral fossae, targeting this specific part of the brain.

Primary Amebic Meningoencephalitis

PAM or the primary amebic meningoencephalitis caused by Naegleria fowleri is a rare and fatal disease of the central nervous system (CNS). N. fowleri attaches itself to the olfactory nerve once it has entered the CNS after insufflation of infected water and migrates towards the anterior cerebral fossae, where it causes inflammation, necrosis, and hemorrhage leading to high mortality with approximately 95% fatality rate.

Symptoms

PAM symptoms usually manifest approximately five days after infection which starts with a headache, fever, nausea, and vomiting that makes PAM indistinguishable from bacterial meningitis due to similar symptoms.

Later symptoms include stiff neck, confusion, loss of balance, seizures, and hallucinations. About two-thirds of patients experience altered mental status followed by rapid deterioration to coma and death.

Prevention

When doing water-related activities in bodies of warm freshwater, the risk of PAM can be reduced by limiting the amount of water going through the nose by:

• Simply avoid putting head under water
• Use nose clips or hold your nose
• Avoid activities in warm freshwater when the water temperature is high and the water level is low
• Do not dig or stir up the sediment in shallow, warm freshwater areas