West Nile virus is a mosquito-borne flavivirus that is maintained in an enzootic cycle between mosquitoes and birds. Humans and horses are incidental dead-end hosts.
Cryptosporidia are intestinal parasites infecting a variety of animals (e.g. cattle, sheep, rodents, cats and dogs, but also birds, fish and reptiles). Human infections occur due to Cryptosporidium parvum, a species that also affects domestic animals.
West Nile virus (WNV) infection is a mosquito-borne zoonosis. The virus is transmitted among birds via the bite of infected mosquitoes and incidentally humans and other mammals may become infected.