West Nile virus in livestock and wildlife

West Nile (WN) virus, the causative agent of West Nile fever, a dengue-like infection in humans, is one of the most widely distributed arthropod-borne viruses extending, until recently, from Africa, the Middle East, Europe, and western Asia. WN virus is a natural avian virus transmitted between birds primarily by ornithophilic mosquitoes, although isolations have been reported from mammals and amphibians, other mosquitoes and ticks. This virus has one of the broadest host and vector ranges and historically caused clinical disease in humans and equines only.