West Nile encephalitis in a captive Florida sandhill crane

A 37 year old captive male Florida sandhill crane (Grus canadensis pratensis) housed at the International Crane Foundation exhibited abnormal neurologic signs in the fall of 2006. Despite therapy and supportive care, the neurologic signs worsened and the crane was euthanized after 6 days. Antemortem and postmortem serum was positive for flavivirus antibody, and a cloacal swab was positive for West Nile virus (WNV) by reverse transcriptase polymerase chain reaction (RT-PCR). Pectoral muscle atrophy and multifocal myocardial necrosis were observed at necropsy. Histopathologic findings included inflammatory and necrotic lesions in sections of brain, spinal cord, eye, heart, blood vessels, lung, air sac, esophagus, ventriculus, intestine, thyroid, adrenal, kidney, testicle, and feather follicles. A RT-PCR of brain tissue was positive for WNV. Most of the lesions were consistent with what has been described in birds with WNV, but were more severe and broadly distributed. The impact of WNV on captive crane populations has been variable. Currently, 13 of 15 crane species held in captive centers in the U.S. have been seropositive for WNV, but mortality has been limited to sandhill cranes