Gnathostoma infection after ingestion of raw fish is a probable cause of eosinophilic meningitis in the Brazilian Amazon.

We report a case of eosinophilic meningitis associated with the ingestion of raw fish (Cichla sp.) from the Brazilian Amazon, likely caused by Gnathostoma. A 36-year-old male visited Juruena river on a fishing trip. After 50 days, the patient presented with an intense frontal headache. A cerebrospinal fluid examination revealed 63% eosinophilia. Another individual who ingested raw fish developed linear dermatitis on the abdominal wall. Anti-Gnathostoma serum antibodies were detected, and the patient made a full recovery after treatment with corticosteroids and albendazole. To date, autochthonous Gnathostoma spp. infections in Latin American countries have only caused linear panniculitis. This report raises awareness of gnathostomiasis-causing meningitis.