Studies on eosinophilic meningitis and meningoencephalitis caused by Angiostrongylus cantonensis in Japan

Twenty cases of eosinophilic meningitis or meningoencephalitis suspected of being angiostrongyliasis were recognized in Japan, including 16 cases in Okinawa Prefecture. Among the cases, there was only one proven case in Okinawa. The disease evenly occurred throughout all seasons. Both sexes were equally affected, but 17 cases (more than 80%) occurred among adults. Intentional ingestion of various mollusks and fresh livers of toads for therapeutic reasons were interestingly responsible for 7 cases. The immunological diagnosis was successfully carried out on 9 cases. It was discussed that the cultural and ethnic backgrounds with different ways of life and eating habits determine the prevalence of the disease, and clinical and epidemiological features of the disease among different ethnic groups and geographic areas.