What is PAM and the Brain-Eating Amoeba?

Primary Amebic Meningoencephalitis (PAM), often called the “brain-eating amoeba” infection, is a rare but extremely deadly disease caused by the free-living amoeba Naegleria fowleri. This single-celled organism thrives in warm freshwater environments and can invade the human brain through the nasal passages, leading to rapid destruction of brain tissue.

How Does Infection Happen?

Naegleria fowleri enters the body when contaminated warm freshwater (like from lakes, rivers, hot springs, or poorly maintained pools) is forcefully inhaled through the nose—typically during swimming, diving, or water sports. The amoeba travels along the olfactory nerve, crosses into the brain via the cribriform plate (a bony structure in the skull), and multiplies, causing severe inflammation and tissue damage. It’s not spread person-to-person, through drinking water, or in saltwater. Infections are more common in summer and in warmer regions like the southern U.S. (e.g., Florida and Texas).

Symptoms

Symptoms mimic bacterial meningitis but progress much faster:

• Early (1–5 days after exposure): Severe headache, fever, nausea, vomiting, and stiff neck.
• Later stages: Confusion, loss of balance, seizures, hallucinations, and sensitivity to light.

Without treatment, death usually occurs within 5 days (up to 1–18 days). As of 2024, there have been 167 reported U.S. cases since 1962, with only 4 survivors.

Treatment

PAM is nearly always fatal (97–99% mortality), but early diagnosis improves odds. Treatment involves:

• Intravenous and intrathecal antifungal drugs like amphotericin B.
• Oral miltefosine (an antiparasitic) and other supportive meds (e.g., rifampin, azithromycin).
• Induced hypothermia to reduce brain swelling and experimental drugs like nitroxoline.

If suspected, seek immediate medical care—a spinal tap or brain biopsy confirms it. Contact the CDC for guidance (770-488-7100).

Recent Cases (as of September 2025)

In 2025, India has seen an unusual spike in Kerala state, with over 70 diagnoses and 19 deaths across all ages (from infants to the elderly), linked to contaminated water sources. This outbreak highlights risks in untreated water, but globally, cases remain rare (fewer than 10–15 annually in the U.S.).

Prevention

• Avoid submerging your head in warm, stagnant freshwater; use nose clips if swimming.
• Use boiled or treated water for nasal irrigation (e.g., neti pots).
• Maintain pools and hot tubs properly with chlorine.

For more details, visit the CDC’s Naegleria page.