An Epidemiological Study of Habu-bites in the Amami Islands

Abstract

Epidemiological features of habu-bite in the Amami Islands were investigated. Over a period of 5 years (1972 to 1976) 1285 cases of habu-bite, including 11 deaths, were recorded on Tokunoshima and Amamioshima. The total number of victims was 1265, of which 1246 were attacked once, 18 twice and 1 three times during the 5 year period. Assuming that the frequency of habu-bite per head is a truncated Poisson distribution, the size of the hypothetical population risking habu-bite was estimated by the maximum likelihood method. We obtained the value of 41993, which was approximately 35% of the total population and roughly equal to the size of the farming population. The incidence rate of habu-bite per unit of local population differed greatly according to the community unit (village, town or city), but the rates for the farming population and farming land did not differ greatly among the local communities. Patterns for the seasonal and diurnal distribution of habu-bite clearly indicated that the incidence of bites reflects the activities of both humans and habu.