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.
Cholera is an acute diarrhoeal infection caused by the bacterium Vibrio cholera of serogroups O1 or O139. Humans are the only relevant reservoir, even though Vibrios can survive for a long time in coastal waters contaminated by human excreta.
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.