What are the reservoirs of WNV?

• A. Wild birds, especially Corvids (crows, ravens, jays, magpies)
• B. Domestic dogs and cats
• C. Horses and cattle
• D. Humans only

Answer: (A)

West Nile virus is maintained in nature through an ongoing cycle between mosquitoes and wild birds. Birds serve as reservoirs because they develop enough virus in their blood to infect feeding mosquitoes, allowing the virus to persist and spread. Corvids—crows, ravens, jays, and magpies—are especially important because they often reach high levels of virus in their bloodstream, amplifying transmission and driving outbreaks. Other animals, like domestic dogs and cats, horses, and cattle, can become infected, but their viremia is typically too low to infect mosquitoes, so they don’t sustain transmission and are considered incidental hosts. Thus, the main reservoirs are wild birds, with corvids playing a particularly key role.