What is Naegleria fowleri-caused Amoebic meningitis (also called Primary Amoebic Meningoencephalitis, PAM)?

Amoebic meningitis

• This is a very rare but extremely serious brain infection caused by the free-living amoeba Naegleria fowleri. 

• The amoeba lives in warm fresh water (like lakes, ponds, poorly-treated swimming pools) and typically infects a person when contaminated water enters the nose, then the amoeba travels along the olfactory nerve into the brain. 

• Once inside the brain, it causes severe inflammation (meningoencephalitis) and very rapid brain tissue destruction. The disease progresses extremely fast. 

• While often called “amoebic meningitis”, technically it is meningoencephalitis (inflammation of both the brain substance + membranes) rather than classic bacterial meningitis.

causative organism

brain inflammation caused by the organism

Causes & risk factors

1. The major causative agent: Naegleria fowleri. 
2. Mode of infection: Water containing the amoeba enters the nose (for example when swimming, diving into fresh warm water, or during nasal rinsing with non-sterile water). It is not typically transmitted by drinking the water. 
3. Conditions that favour the amoeba: Warm, stagnant fresh water; poorly chlorinated pools; warm climates raising water temperature. 
4. In the recent Indian context: The state of Kerala has reported a surge in cases — for instance ~80 cases and 21 deaths in 2025. 

Symptoms & clinical progression

• Early symptoms (within a few days after exposure): Headache, fever, nausea, vomiting. 

• Progressive/advanced symptoms: Stiff neck, confusion, seizures, hallucinations, coma. Rapid deterioration is common. 

• Because the disease progresses so quickly and is so rare, diagnosis often occurs late, making management very difficult. 

• Mortality is extremely high historically (often cited > 90%), although early and aggressive treatment may improve chances. 

Prevention & control

Because treatment options are limited and outcomes often poor, prevention is key. Some important measures:

• Avoid swimming or diving in warm stagnant fresh water bodies (ponds, lakes, rivers) especially when water is warm and flows slowly. 

• If entering such water, avoid letting water go up the nose — e.g., keep head above water, use nose clips if possible. 

• Use only boiled, cooled, or sterile/distilled water for nasal rinsing (e.g., neti pot), ablutions, or similar practices; do not use untreated tap or stored water. 

• Ensure swimming pools, hot-tubs, and other recreational water bodies are well-maintained and properly chlorinated/disinfected. 

• Public-health level: Monitoring water quality, surveying warm fresh-water bodies for the amoeba, ensuring well-water, storage tanks, and supply systems are safe. 

• Awareness: Because the disease is rare, many aren’t aware of it — public education about risk environments, symptoms, and prompt medical care is critical. 

Treatment & recent developments

• There is no standard, guaranteed treatment; historically, data are limited. 

• Some centres have used a combination of drugs including amphotericin B and more recently off-label use of Miltefosine in suspected cases, with some success noted in Kerala. 

• Early detection and aggressive management are critical for any chance of survival.

Recent incident in Kerala, India

• The state of Kerala has had a surge of cases: For 2025, ~80 cases and 21 deaths were reported in the state. 

• Experts link this rise to warmer temperatures (which favour the amoeba), more intensive testing (so more detection), and perhaps higher exposure in warm water bodies. 

• The public health response includes: setting up more diagnostic labs, issuing technical guidelines for early detection / treatment / prevention, and emphasising chlorination / water safety.