West Nile Virus in Alligator, Alligator mississippiensis, Ranches from Louisiana

Abstract

ABSTRACT West Nile virus (WNV) has been reported to affect various crocodilian species including the American alligator, Alligator mississippiensis, the Nile crocodile, Crocodylus niloticus, and the Morelet's crocodile, Crocodylus moreletii. In the Fall of 2003 an increased number of mortalities were observed at various alligator ranches in Louisiana. Affected animals were reported to have neurologic signs followed by death. At the time West Nile virus (WNV) had already been diagnosed in alligators from Georgia and Florida, but not Louisiana. This report outlines the findings of physical exam, necropsy, histopathology and diagnostic tests of affected animals. Viral isolation, real time RT-PCR and immunohistochemistry have proven to be useful tests for diagnosing WNV in alligators. One interesting aspect of these cases is that only one of the four affected facilities had alligators hatched in Louisiana. The other three had imported hatchlings from Florida and Texas.