An indirect estimation of the developmental time of Haemagogus janthinomys (Diptera : Culicidae), the main vector of yellow fever in South America

摘要

Yellow fever is a re-emergent disease in many South American countries where its main vector is Haemagogus janthinomys. Epizootics and epidemics have long been associated with the onset of the rainy season, when mosquito densities are higher. Thus, a more precise understanding of the relationship between rainfall and mosquito densities is necessary to evaluate the risk of transmission. Mosquitoes were collected when landing on a volunteer, almost daily for three hours, from 18 June, 1986 to 16 December, 1987, at canopy level, in a rainforest station in Eastern Brazilian Amazonia. A total of 4079 mosquitoes from 25 different species were captured during 547 collecting sessions, and Hg. janthinomys accounted for 18.78% (766 individuals). Cross-correlations were looked for between mosquito densities and rainfall, and auto-correlation calculations were carried out with the mosquito collection series. The first analysis showed a significant correlation index until the 55th day, with two peaks at 11-13 and 20-24 days. The auto-correlation of the mosquito series showed a regularly decaying correlation index, which remained significant until day lag 34. The study showed indirectly that under a rainforest rainfall regime, the development of female Hg. janthinomys from egg to adult takes 11-13 days.