河南省基本消灭丝虫病后传播潜力的研究

THE TRANSMISSION POTENTIAL OF FILARIASIS IN THE CONTROLLED AREAS OF HENAN PROVINCE

河南省基本消灭丝虫病后，在８县（市）设定了８个监测点，在不再采取任何有组织的病原防治措施的条件下，对丝虫病进行了纵向流行病学监测，在１９８８～１９９５年连续８年的监测中，１０例残存微丝蚴血症者于６年内陆续转阴，无新发微丝蚴血症，１９９３～１９９５年人群微丝蚴率为０。蚊媒幼丝虫自然感染率保持在极低值（０．０１％～０），８年共检出１５只阳性蚊，检出幼丝虫１８条，均为Ⅰ～Ⅱ期幼虫。在蚊种构成上各监测点优势蚊种仍以淡色库蚊为主，其次为中华按蚊，致倦库蚊和嗜人按蚊很少。露宿人群蚊媒叮人率波动较大，为７．２０只～３６０．６０只／人·夜；帐内人群蚊媒叮人率一般在１只／人·夜左右。经产蚊比率为２７．２７％～８８．１０％。测算每人传播季节受感染性蚊媒叮咬的次数为０，结果显示在河南流行区内丝虫病传播已被阻断。同时也与国内报道的当微丝蚴率降至１％以下，残存微丝蚴血症者可于３～５年内陆续转阴的结论相一致。因此，可以推论基本消灭丝虫病地区，只要经历一定的时间，丝虫病可望达到自然消灭。

After filariasis was basically controlled(the microfilarial rate was below 1%)in Henan Province in 1987, longitudinal surveillance of the disease has been carried out. Eight administrative villages in 8 counties were selected as surveillance sites. From 1988 to 1995, etiologic and mosquito vector surveys were made continuously in all sites where no control measures was taken. Ten residual microfilaremiae became negative gradually in the first 6 years and no new microfilaremia occurred.The microfilarial rate of population in the sites was 0 from 1993 to 1995. The natural infection rates of filarial larvae in mosquito vector were 0.01%～0. During the 8 years, 15 vector mosquitoes were positive with total of 18 filarial larvae which were all of stage Ⅰ and Ⅱ. C. pipiens pallens was the main vector, the second was A. sinensis, with a small number of C. fatigans and A. anthropophagus. The man-biting rates of mosquito for outdoor sleepers were 7.20～360.60 mosquitoes per man per night. For sleepers inside mosquito-net, it was about 1. The proportion of multiparous mosquito ranged from 27.27%to 88.10%. According to the data described above, the man-biting rate of mosquito which contained filaria L3 was 0.It suggested that after the microfilarial rate was below 1%,the residual microfilaremia became negative gradually in 3￣6years,and the transmission of the disease was blocked. Therefore , in the areas where filariasis was basically controlled, elimination of the disease was attainable within sight.