1963年度岡山市および倉敷市における日本脳炎の流行と蚊の季節的消長

Mosqnitoes were collected by light-trapping twice a week during nights from May through September, 1963, totally 30 times from two spots of Kurashiki City and 32 times from one spot of Okayama City. The number of mosquitoes collected was 1, 563 and 2, 882 from Hama and Mizushima in Kurashiki City respectively, and 9, 185 from Okayama City. Culex tritaeniorhynchus first occurred at the end of May at Mizushima, in the middle of June at Okayama, and in the beginning of July at Hama, and reached their peak in July, on the 23rd at Mizushima, on the 29th at Okayama, and on the 30th at Hama. While the first incidence of Japanese B encephalitis at Okayama and Mizushima was reported approximately three weeks after the maximum occurrence of the mosquito, it was as early as on the 20th of July at Hama being ten days ahead of the peak.