Flaviviruses

摘要: Flaviviruses are a group of arthropod-borne viruses that have demonstrated a propensity to spread and establish in new geographic areas. This invasiveness of flaviriruses is due to the complex interplay of a number of different factors, some of which are properties of the viruses, and others that are the consequences of human activities. The viral factors include the ability of some members of the genus to use a wide spectrum of vector mosquito species and vertebrate host reservoirs, especially when establishing in new ecosystems, their ability to survive and replicate in vectors and hosts under a variety of environmental conditions, and the ability of some members to be transported between regions and continents through migratory bird hosts. Human activities are a major component of the interplay, and include the dispersal and spread of the viruses in infected mosquitoes and/or infected passengers on ships and planes, by commercial transport of animals and goods, and by providing new mosquito breeding sites through changes in land use such as in newly-developed rice paddies or areas of irrigated agriculture, or in urban shanty-towns. Also important has been the spread of major mosquito vector species and their subsequent colonization of new areas, as seen by the widespread global infestation of Aedes albopictus on all continents, frequently through the international trade in old automobile tires, and of Ae. aegypti mosquitoes which may move between regions and continents in containers on cargo ships or in aircraft holds. The latter is perhaps the most important vector mosquito species,