Abstract:
Arthropod-transmitted viruses (Arboviruses) are important causes of disease in humans and
animals, and it is proposed that climate change will increase the distribution and severity of arboviral
diseases. Orbiviruses are the cause of important and apparently emerging arboviral diseases of livestock,
including bluetongue virus (BTV), African horse sickness virus (AHSV), equine encephalosis virus (EEV),
and epizootic hemorrhagic disease virus (EHDV) that are all transmitted by haematophagous Culicoides
insects. Recent changes in the global distribution and nature of BTV infection have been especially
dramatic, with spread of multiple serotypes of the virus throughout extensive portions of Europe and
invasion of the south-eastern USAwith previously exotic virus serotypes. Although climate change has been
incriminated in the emergence of BTV infection of ungulates, the precise role of anthropogenic factors and
the like is less certain. Similarly, although there have been somewhat less dramatic recent alterations in the
distribution of EHDV, AHSV, and EEV, it is not yet clear what the future holds in terms of these diseases,
nor of other potentially important but poorly characterized Orbiviruses such as Peruvian horse sickness
virus.
