Outbreak of Naegleria fowleri in Kerala, India, 2025

Naegleria fowleri is a free-living thermophilic amoeba found globally in warm freshwater environments. Infection in humans results in primary amoebic meningoencephalitis (PAM), a rare but severe disease impacting the central nervous system, with a case fatality rate of approximately 97%. This watching brief analyses the N fowleri outbreak in Kerala, India, during the period 1st January to 31st October 2025. A total of 153 laboratory-confirmed cases of N fowleri infection were reported in Kerala during this period, representing an increase in incidence compared to the historical baseline data. Despite the high number of cases, the case fatality rate during this outbreak was 21.6%, substantially lower than the global average. This report examines the epidemiological patterns, potential environmental and climate factors contributing to this outbreak and the public health responses implemented.