Experimental West Nile virus infection in Eastern Screech Owls (Megascops asio)

Avian Diseases
By: , and 



Eastern Screech Owls (EASOs) were experimentally infected with the pathogenic New York 1999 strain of West Nile virus (WNV) by subcutaneous injection or per os. Two of nine subcutaneously inoculated birds died or were euthanatized on 8 or 9 days postinfection (DPI) after <24 hr of lethargy and recumbency. All subcutaneously inoculated birds developed levels of viremia that are likely infectious to mosquitoes, with peak viremia levels ranging from 105.0 to 109.6 plaque-forming units/ml. Despite the viremia, the remaining seven birds did not display signs of illness. All birds alive beyond 5 DPI seroconverted, although the morbid birds demonstrated significantly lower antibody titers than the clinically normal birds. Cagemates of infected birds did not become infected. One of five orally exposed EASOs became viremic and seroconverted, whereas WNV infection in the remaining four birds was not evident. All infected birds shed virus via the oral and cloacal route. Early during infection, WNV targeted skin, spleen, esophagus, and skeletal muscle. The two morbid owls had myocardial and skeletal muscle necrosis and mild encephalitis and nephritis, whereas some of the clinically healthy birds that were sacrificed on 14 DPI had myocardial arteritis and renal phlebitis. WNV is a significant pathogen of EASOs, causing pathologic lesions with varying clinical outcomes.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Experimental West Nile virus infection in Eastern Screech Owls (Megascops asio)
Series title Avian Diseases
Volume 50
Issue 2
Year Published 2006
Language English
Contributing office(s) Patuxent Wildlife Research Center
Description 252-258
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Avian Diseases
First page 252
Last page 258