[Study on the thresholds of malaria transmission by Anopheles anthropophagus in Hubei Province].

OBJECTIVE: To study the thresholds and potential of malaria transmission by Anopheles anthropophagus in Hubei Province and provide indicators for the disease surveillance, early warning, prevention and control in the locality. METHODS: From July to August 2001, field investigations on vectors and malaria situation were carried out in the village of Yanjiafan, Suizhou City, where the malaria incidence was high. The entomological investigations included the man-biting rate, the proportion of parous anophelines, the human blood index and the blood preference. 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. Based on the formula of basic reproductive rate, the critical man-biting rate was estimated. RESULTS: 92.6% (63/68) of An. anthropophagus were found to have human blood meals, it occupied 91.5% (97/106) of the mosquitoes in human dwellings, its human blood index and vectorial capacity were 12.5 times (0.50/0.04) and 6.5 times (0.9448/0.1449) higher than those of An. sinensis. The critical man-biting rate was 0.2823 and the adjusted man-biting rate was 3.5 times of its critical man-biting rate (0.9892/0.2823). The malaria incidence was 0.65% (12/1844) and the parasite rate in pupils was 0.51%(1/198). CONCLUSION: A reduction of the adjusted man-biting rate of An. anthropophagus by 71.5% is needed for interrupting malaria transmission by this vector in the study area.