The body condition of the New York exotic birds that succumbed to WNV ranged from slightly to moderately thin. Affected organs included the brain, heart, spleen, intestine, pancreas, lung and kidney. Cerebral hemorrhage was a frequent finding. This hemorrhage may have been diffuse or localized to the supraoccipital region, or it may have taken the form of a subdural hematoma in the area of the cerebellum. Several birds also have myocardial lesions, consisting of multiple pale foci, pale streaks or a mottled appearance of the heart wall.
Many birds have mild to severe splenomegaly.
Frequently, intestinal lesions consisting of focal or diffuse hemorrhage were also present. The kidneys of affected birds were often swollen or congested, and the lungs were often congested, edematous or hemorrhagic. In the nervous system, the cerebellum proved to be the preferred site, tending to harbour the most severe lesions of all. However, crows and magpies proved to be the exception to this rule, for reasons unknown. Curiously, the neurologic signs of the affected birds did not correlate with the cerebellar lesions found at autopsy.