West Nile Virus Outbreak in North American Owls, Ontario, 2002

Gancz, Ady Y.; Barker, Ian K.; Lindsay, Robbin; Dibernardo, Antonia; McKeever, Katherine; Hunter, Bruce

doi:10.3201/eid1012.040167

Cited by 72 publications

(66 citation statements)

References 21 publications

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“…In this study, 100% (9/9) of subcutaneously inoculated EASOs became viremic; 40% (2/5) of the initial group became clinically ill and maintained a detectable viremia for at least 7 days before death. Although previous reports of WNV-related deaths in other North American owl species have shown morbidity and mortality (6), existing reports of WNV-attributed death in EASOs are rare (7).…”

Section: Discussionmentioning

confidence: 83%

“…In one survey at a captive owl facility, there was no mortality among naturally infected EASOs, although a considerable fraction was WNV seropositive, indicating exposure and survival (7). In this study, 100% (9/9) of subcutaneously inoculated EASOs became viremic; 40% (2/5) of the initial group became clinically ill and maintained a detectable viremia for at least 7 days before death.…”

Section: Discussionmentioning

confidence: 84%

“…The susceptibility of different raptor species, including acute and chronic response to WNV infection, remains poorly understood. Although natural WNV infection in raptors (4,6,7,14,16,17) has been documented, reports of cases with known infection histories in raptors are sparse (9,13).…”

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confidence: 99%

“…The rate of clinical WNV cases in some raptor species at breeding facilities and rehabilitation centers in North America has been high (6,7,16,17), but little information is available as to the pathogenesis of WNV infection in these birds. Among native North American owl species, great horned owls (Bubo virginianus) develop high-level viremia following infection with WNV and are likely a competent reservoir host (9,13).…”

mentioning

confidence: 99%

“…Raptors, including owls, have been reported to experience morbidity and mortality because of infection with West Nile virus (WNV; genus Flavivirus, family Flaviviridae) (6,7). Past experimental work with WNV and raptors has not resulted in overt disease, although it demonstrated that several raptor species can serve as competent amplifying hosts (9,13).…”

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Experimental West Nile Virus Infection in Eastern Screech Owls (Megascops asio)

et al. 2006

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SUMMARY. 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 10 5.0 to 10 9.6 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. RESUMEN. Infección experimental con el virus del oeste del Nilo en un tecolote oriental (Megascops asio).Mediante inyección subcutánea o por la vía oral, se infectaron experimentalmente tecolotes orientales con la cepa patógena (New York 1999) del virus del oeste del Nilo. Dos de nueve aves inoculadas subcutáneamente murieron o fueron sacrificadas 8 o 9 días posteriores a la infección después de menos de 24 horas de letargia y recumbencia. Todas las aves inoculadas subcutáneamente desarrollaron niveles de viremia considerados infecciosos para mosquitos, con picos de viremia en el rango de 10 5.0 a 10 9.6 unidades formadoras de placa por ml. A pesar de la viremia, las 7 aves restantes no desarrollaron signos de la enfermedad. Todas las aves vivas resultaron serológicamente positivas 5 días posteriores a la inoculación, sin embargo, las aves enfermas mostraron títulos de anticuerpos significativamente menores que las aves clínicamente normales. Las aves alojadas en la misma jaula de las aves infectadas no se infectaron. Uno de cinco tecolotes orientales expuestos por vía oral entró en viremia y fue serológicamente positivo, mientras que en el resto de los animales la infección con el virus del oeste del Nilo no fue evidente. Todas las aves infectadas diseminaron el virus por la ruta oral y cloacal. En los estados iniciales de la infección el virus del oeste del Nilo afectó la piel, el bazo, el esófago y el músculo esquelético. Los dos tecolotes enfermos mostraron necrosis del músculo esquelético y cardíaco, así como encefalitis y nefritis leves, mientras algunas de las aves clínicamente sanas que fueron sacrificadas 14 días posteriores a la infección,...

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Section: Discussionmentioning

confidence: 83%

Section: Discussionmentioning

confidence: 84%

mentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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