When crows are infected, unlike with most birds, horses or people, they tend to die. Thus, crow deaths may be an indicator of WNV activity in an area. For reasons that are unknown, a high percentage of crows that become infected with WNV develop severe infection, become ill and die. Most birds and humans develop few if any symptoms, and only a small percentage develop severe, life threatening infection. American crows are found throughout central and eastern North America, wintering as far north as southern Maine and the Great Lakes region.
American crows are large, black, perching birds with robust beaks and a fan-shaped tail.
Both sexes are similar in appearance although females are slightly smaller. Crows cannot transmit this disease to humans. They must first be bitten by an infected mosquito that must then bite a human to possibly spread the disease. Even then, most humans will not show the effect of the disease. The DEP and the Department of Public Health are advising residents who find dead crows or other birds to report this to their local health department during regular working hours.