皖北中华按蚊传播疟疾密度阈值的研究

目的研究皖北中华按蚊传播疟疾密度阈值,为当地疟疾监测、预警与防制提供合理的评价指标。方法选取安徽北部中华按蚊分布区疟疾发病率较高的亳州市蒙城县立仓镇路楼村为调查点,于2005年8～9月现场调查媒介按蚊的叮人率、经产蚊比例、人血指数,调查人群疟疾发病率、原虫率以及疟疾患者发病至接受治疗的平均间隔期,收集观察期间的平均气温数据。根据基本繁殖率概念计算以媒介按蚊临界叮人率为指标的传播疟疾密度阈值。结果中华按蚊的人血指数为0.1771,平均经产蚊比例为0.51,当地中华按蚊的实际叮人率为11.1877、临界叮人率为7.6340,实际叮人率是临界叮人率的1.47倍。结论安徽北部试点中华按蚊的实际叮人率需要降低47%以上,才能阻断当地中华按蚊引起的疟疾传播。

Study on Threshold Density of An.sinensis for Transmission of Malaria in the Northern Anhui Province

Objective To study the threshold density of A n.sinensis for transmission of malaria in the northern Anhui Province and provide indicators for the disease surveillance, early warning, prevention and control. Method From August to September 2005, field investigations on vectors and malaria surveillance were carried out in the Lulou Village of Licang Town, Mengcbeng County in the northern Anbui Province, where the incidence of malaria was high. The entomological investigations included the man-biting rate, the proportion of parous anophelines, the human blood index and the blood preference were performed. The others included malaria incidence and parasite rate in human population, the intervals from episode to treatment of the cases, and collection of data on the mean temperature in the area were also investigated. Based on the formula of basic reproductive rate, the critical man-biting rate was estimated. Result The human blood index for An.sinensis was 0.1771 and the mean muhiparous ratio was 0.51. In study field site, the adjusted human-biting rate for A n.sirtensis was 11.1877 and the critical human-biting rate was 7.6340, the adjusted human-biting rate was 1.47 times of its critical human-biting rate. Conclusion A reduction of the adjusted human-biting rate of An.Sinensis by 47% is needed for interrupting malaria transmission by this vector in the study area.