Coexistence of Aedes aegypti and Aedes albopictus in Jinghong City, Yunnan Province: A Survey of Aedes aegypti Invasion

Abstract

We conducted this study to confirm that Aedes aegypti has invaded and colonized in Xishuangbanna, Yunan province, China. And we conducted a larval survey for dengue mosquito vectors, Ae. aegypti and Ae. albopictus, to assess on possible competition for breeding sites between these both species in urban environment in Jinghong city. The study was carried out at least once a month in February and March, November and December, and three times for each month from April to October in 2014 in five communities in the municipality of Jinghong city. No less than 50 houses were surveyed each time in one place. We collected immature stages of mosquitoes from all types of breeding sites in houses and their premises. Morphological species identification was carried for Ae. aegypti and Ae. albopictus. Both species occurred in all surveyed areas. Aedes aegypti has occupied a considerable composition (67.75%) since the uncertain time of its first invasion to Jinghong city. Aedes aegypti was predominant species indoor (74.19%), but also presented in surrounding environment (25.81%); while Ae. albopictus favored the outdoor environment (54.55%) as well as in houses (45.45%). We gave the preference water containers (tires) for dengue vectors, described different distribution in different investigated places, and showed with monthly variance by indices of BI and CI. We gave our rational explanation for the variance with raining in this area, Aedes keep a high density value during the rainy season. For both dengue vectors, the possibility cannot be excluded that the invasion of Ae. aegypti in the city might lead to a decrease or elimination of Ae. albopictus in houses and dwellings. Furthermore, we also found that both dengue vectors have already occupied the breeding sites in houses and their premises with water container in Jinghong city, and both should be managed during dengue epidemic season. These findings from this study are relevant for dengue vector control programs