Autor(es): Weaver Scott C, Reisen William K

Resumo: Arthropod-borne viruses (arboviruses) are important causes of human disease nearly worldwide. All arboviruses circulate among wild animals, - many cause disease after spillover transmission to humans - agriculturally important domestic animals that are incidental or dead-end hosts. Viruses such as dengue (DENV) - chikungunya (CHIKV) that have lost the requirement for enzootic amplification now produce extensive epidemics in tropical urban centers. Many arboviruses recently have increased in importance as human - veterinary pathogens using a variety of mechanisms. Beginning in 1999, West Nile virus (WNV) underwent a dramatic geographic expansion into the Americas. High amplification associated with avian virulence coupled with adaptation for replication at higher temperatures in mosquito vectors, has caused the largest epidemic of arboviral encephalitis ever reported in the Americas. Japanese encephalitis virus (JEV), the most frequent arboviral cause of encephalitis worldwide, has spread throughout most of Asia - as far south as Australia from its putative origin in Indonesia - Malaysia. JEV has caused major epidemics as it invaded new areas, often enabled by rice culture - amplification in domesticated swine. Rift Valley fever virus (RVFV), another arbovirus that infects humans after amplification in domesticated animals, undergoes epizootic transmission during wet years following droughts. Warming of the Indian Ocean, linked to the El Niño-Southern Oscillation in the Pacific, leads to heavy rainfall in east Africa inundating surface pools - vertically infected mosquito eggs laid during previous seasons. Like WNV, JEV - RVFV could become epizootic - epidemic in the Americas if introduced unintentionally via commerce or intentionally for nefarious purposes. Climate warming also could facilitate the expansion of the distributions of many arboviruses, as documented for bluetongue viruses (BTV), major pathogens of ruminants. BTV, especially BTV-8, invaded Europe after climate warming - enabled the major midge vector to exp- is distribution northward into southern Europe, extending the transmission season - vectorial capacity of local midge species. Perhaps the greatest health risk of arboviral emergence comes from extensive tropical urbanization - the colonization of this exp-ing habitat by the highly anthropophilic (attracted to humans) mosquito, Aedes aegypti. These factors led to the emergence of permanent endemic cycles of urban DENV - CHIKV, as well as seasonal interhuman transmission of yellow fever virus. The recent invasion into the Americas, Europe - Africa by Aedes albopictus, an important CHIKV - secondary DENV vector, could enhance urban transmission of these viruses in tropical as well as temperate regions. The minimal requirements for sustained endemic arbovirus transmission, adequate human viremia - vector competence of Ae. aegypti -/or Ae. albopictus, may be met by two other viruses with the potential to become major human pathogens: Venezuelan equine encephalitis virus, already an important cause of neurological disease in humans - equids throughout the Americas, - Mayaro virus, a close relative of CHIKV that produces a comparably debilitating arthralgic disease in South America. Further research is needed to underst- the potential of these - other arboviruses to emerge in the future, invade new geographic areas, - become important public - veterinary health problems.

Palavras-Chave: Arbovirus; Emergence; Epidemic; Flavivirus; Alphavirus; Climate change

Imprenta: Antiviral Research, v. 85, n. 2, p. 328-345, 2010

Identificador do objeto digital: 10.1016/j.antiviral.2009.10.008

Descritores: Chikungunya virus - Arbovirus ; Chikungunya virus - Cytopathology ; Chikungunya virus - Infectious diseases ; Chikungunya virus - Viral infections ; Chikungunya Virus - Virus ; Chikungunya virus - Transmission ; Chikungunya virus - Chikungunya fever ; Chikungunya virus - Dengue ; Chikungunya virus - Epidemic ; Chikungunya virus - Epidemiology ; Chikungunya virus - Public health

Data de publicação: 2010

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