Transmission
Haematophagous insects play a central role in the transmission of all VEE viruses
o epizootic strains have been isolated from the genera: Aedes, Anopheles, Culex, Deinocerites, Mansonia and Psorophora
o mechanical transmission of epizootic VEE has been demonstrated for blackflies (Simulium spp.)
o role of ticks uncertain though Amblyomma and Hyalomma species have been infected experimentally with both enzootic and epizootic strains of VEE
Enzootic/endemic or Sylvatic cycle: enzootic VEE variants and subtypes cycle in tropical ecosystems among rodents, and perhaps birds, by the feeding of mosquitoes