Brain-eating amoeba

Brain-eating amoeba, scientifically known as Naegleria fowleri, is a free-living, thermophilic (heat-loving) amoebic organism that can cause a rare and devastating infection of the brain called primary amoebic meningoencephalitis (PAM). This infection, although rare, is often fatal and primarily affects individuals who swim or dive in warm freshwater places, such as lakes and hot springs.

Naegleria_fowleri_lifecycle_stages

Overview

Naegleria fowleri is found worldwide, most commonly in warm freshwater (such as lakes, rivers, and hot springs), soil, and poorly maintained or unchlorinated pool water. This amoeba can travel up the nose to the brain and spinal cord while swimming or diving. It destroys brain tissue, causing brain swelling and, in most cases, death.

Infection Process

The infection process begins when water containing Naegleria fowleri is aspirated, allowing the amoeba to enter the nasal passages. From there, it migrates to the brain via the olfactory nerves, breaching the blood-brain barrier. Once in the brain, it causes meningoencephalitis, a dangerous inflammation of the brain tissue. Symptoms start with severe frontal headache, fever, nausea, and vomiting, quickly progressing to stiff neck, seizures, altered mental status, and coma. The disease progresses rapidly, often leading to death within about five days from the onset of symptoms.

Diagnosis and Treatment

Diagnosis of PAM is challenging, often made posthumously. It involves examining cerebrospinal fluid (CSF) obtained via lumbar puncture, brain imaging, and polymerase chain reaction (PCR) to detect Naegleria fowleri DNA. Treatment is aggressive and must be initiated promptly upon suspicion of infection. It typically includes a combination of antimicrobial agents, such as amphotericin B, rifampicin, and miltefosine. However, even with treatment, the survival rate remains low.

Prevention

Preventive measures focus on minimizing exposure to potentially contaminated water. Recommendations include avoiding water-related activities in warm freshwater during hot periods, using nose clips or holding the nose shut while swimming, and avoiding stirring up sediment in shallow warm freshwater areas.

Epidemiology

Cases of PAM are rare but have a high mortality rate. Infections have been reported globally, with a higher incidence in warmer climates, correlating with the preferred habitat of Naegleria fowleri. Despite its lethality, the overall risk of contracting PAM is extremely low.

See Also

• Amoebic meningoencephalitis
• Meningitis
• Encephalitis
• Waterborne diseases