关键词: 嗜人按蚊, 环境, 疟疾

Abstract: This paper analyses the relationship between the geographical distribution of An.thropophagus and environmental factors in Sichuan Province systematically.Many environmental factorsare concerned: hydrographic net, human population density, farming land type, soil texture and altitudeabove sea level.1.Mostly, An.anthropopagus was distributed at the areas of the Minjiang Valley, theChangiiang trunk drainage in the southern part of sichuan Basin and the Tuojiang Valley.The ratio of An.anthropophagus in human dwellings showed some differences among these three water systems:53.86% and 61.90% and 22.74% respectively.2.An.anthropophagus was most widely spread in theareas with a human population density of 100 ～ 600 people per square kilometer from 1951 to 1990.During 1971 ～ 1980, An.anthropophagus in human dwellings was mainly distributed in the areas of humanpopulatuion density more than 600 people per square kilometer with a ratio of An.anthropophagus ashigh as 45.71%.3.An.anthropophagus was largely distributed in new alluvial soil, Chengdu clay, yellowand purple soil; only some in brown-podzol earth, marshy soil, mountain-meadow soil and podzolic brownforest soil.It seems that the distribution of An.anthropophagus is in relation to soil texture, but the soiltype is not a decisive factor.4.An.anthropophagus was chiefly distributed in plain, hilly land and lowmountain less than 1000 meters above sea level, where there are irrigated fields during winter.No An.anthropophagus was, however, found at the altitude above 1000 meters and dryland areas.The resultsshowed that the geographical distribution of An.anthropophagus was significantly influenced by the altitude above sea level and the existence of irrigated field.Nevertheless, some cities (ortowns) with irrigatedfields still had no An.anthropophgus found below the altitude of 1000 meters.Hence, besides the factors mentioned above, other factors such as meterological factor may play some important role in the geographical distribution of An.anthropophagus.5.Malaria incidence in the areas with An.anthropophagus had a close relation to the ratio of An.anthropophagus in human dwellings.In the MinjiangValley and the Changjiang trunk drainage, the ratio of An.anthropophagus was much higher than it inthe Tuojiang Valley, Jialing Valley and the Wujiang Valley.Proportionally, malaria incidence in the former areas was also much higher than it in the latter areas.In addition, based on the density of populationliving in the areas with An.anthropophagus, the denser the population, the lower the incidence and viceversa.Reasons are perhaps due to differnt economic level, cilivization degree and public health care between the two groups.