Which birds are most vulnerable to West Nile Virus in the North American strain?

• A. Crows and blue jays most vulnerable in N. American strain.
• B. Penguins are most vulnerable.
• C. Sparrows are most vulnerable.
• D. Ducks are most vulnerable.

Answer: (A)

West Nile Virus in the North American lineage tends to hit certain birds harder because of how the virus replicates to high levels in them, making them highly vulnerable and often fatal. Crows and blue jays, which are corvids, consistently develop very high viremia and die at higher rates than many other birds, so they stand out as the most vulnerable group. This makes them especially important as sentinels for local transmission. Penguins aren’t typical North American wild hosts and aren’t used as primary indicators in this context. Sparrows and ducks can be infected as well, but they generally experience lower mortality and viral loads compared with corvids, so they’re less vulnerable overall.