Epidemiological studies on factors correlated with the snake bite by habu trimeresurus flavoviridis in amami islands japan
Tanaka, H.; Hayashi, Y.; Wada, Y.
Snake 11(1): 79-83;130-131
The occurrence of bites by habu, T. flavoviridis on the Amami Islands is decreasing on Amami Oshima and increasing on Tokunoshima. The bite cases in the latter become more than in the former since 1960 showing an incidence per 1000 population of 6.77 and 1.38, respectively, on the 2 islands in 1976. The present study deals with epidemiological identification of the common factor in the 2 islands governing this change of the snake bite. The correlations were examined between the bite cases by locality from 1972 to 1976 and area of cultivated farming field, total population, the population of farmers, cultivated field per farmer and total farming field (cultivated and abandoned fields) in 1976 by each locality. No correlation was found in the total population in locality. The correlations were high in total farming field, the population of farmers and cultivated farming field in each locality. With these factors, high correlations were noticed in total number of bite cases followed by the cases bitten outside of houses. The correlation coefficients between snake bite in the locality and population of farmers in the corresponding locality, total farming field and cultivated farming field were 0.948, 0.943 and 0.934, respectively. Correlations between snake bites by locality in 1955, 1965 and 1975 and corresponding areas of cultivated farming field or the population of farmers were examined and the coefficients were 0.8682 and 0.7436, respectively. The populations of farmers were not considered to be the common factor because they were decreasing on both islands while the number of bite cases decreased on Amami Oshima and increased on Tokunoshima. Since the change of cultivated farming field showed the similar trend with that of snake bites, cultivated field was identified as having a close correlation with snake bite frequency.