Natural West Nile Virus Infection in a Captive Juvenile Arctic Wolf (Canis Lupus)

Abstract

Abstract.A case of West Nile virus (WNV) infection in a captive 4-month-old Arctic wolf (Canis lupus) is described. The animal had vomiting, anorexia, and ataxia before death. Histopathology revealed multifocal severe renal lymphoplasmacytic vasculitis, mostly affecting small arterioles, with fibrinoid degeneration of some vessel walls. Many small foci of gliosis were detected in the cerebral cortex. West Nile virus was demonstrated in the kidneys and cerebrum by immunohistochemistry and polymerase chain reaction. The described renal changes represent a novel pathological finding of WNV infection. West Nile virus (WNV), a flavivirus transmitted by mosquito bite, was reported for the first time in North America in 1999. [3][4][5] Outbreaks have affected horses and wild indigenous and captive exotic birds mostly. Other mammals, like cats, squirrels, rabbits, and chipmunks, are known to be infected occasionally. 3,4 In 2002, the infection was detected in a captive seal at a US aquarium and for the first time in a reptile, an alligator, in Florida. West Nile virus-infected birds were detected for the first time in the province of Qué-bec (Canada) during the summer of 2002. The pathological, immunohistochemical, and polymerase chain reaction (PCR) findings of a natural WNV infection in a captive juvenile Arctic wolf are described.A wolf pup was born in February 2002 and kept in captivity with its mother in Southern Québec. The pup was vaccinated twice against canine distemper virus (CDV), canine hepatitis virus (CHV), and canine coronavirus (CC). At 4 months, the animal had nasal and ocular discharge, vomiting, anorexia, and lethargy. It was isolated and received supportive treatment for 4 days, with some improvement. The clinical signs progressed, the pup developed ataxia, and died 24 hours later. The animal was sent to the Diagnostic Service of the Faculté de médecine vétérinarie, Université de Montréal, St.-Hyacinthe, Québec, Canada, for necropsy.The wolf was in poor body condition. There was abundant bilateral grayish mucoid exudate at the nasal turbinates. The liver was yellow, friable, and mildly enlarged. Small and large intestinal content was largely uncoagulated blood. The intestinal serosa appeared mildly granular. Tissue samples were fixed in 10% buffered formalin and embedded in paraffin. Sections were cut at 3 m and stained with hematoxylin-eosinsaffron (HES).Fresh samples of ileum, liver, and nasal turbinates were submitted for aerobic culture and Leptospira spp. isolation. Cultures of Escherichia coli and Staphylococcus spp. developed from the nasal turbinates. No parasites or ova were detected in feces by flotation. Direct fluorescent antibody examination of sections of small intestine was negative for CC and canine par-

Natural and Experimental West Nile Virus Infection in Five Raptor Species

“…It has been documented, however, in an Arctic wolf (Canis lupus) with severe renal lymphoplasmacytic vasculitis with fibrinoid degeneration of vessel walls (Lanthier et al, 2004), while farmed alligators had heterophil stasis within blood vessels in brain and meninges (Miller et al, 2003). Immunohistochemistry revealed WNV antigen in smooth muscle cells of arteries in red-tailed hawks and Cooper's hawks (Accipiter cooperi) (Wü nschmann et al, 2004).…”

Comparative Pathology of West Nile Virus in Humans and Non-Human Animals

“…In a case report of a dog, polioencephalomyelitis and myocarditis were accompanied by vasculitis, pancreatitis and plasmacytic synovitis (inflammation of the articular synovial surface) [151]. In an arctic wolf, renal vasculitis was a significant finding [152].…”

Review of West Nile virus circulation and outbreak risk in Madagascar: Entomological and ornithological perspectives

“…The first outbreak was reported from Israel in 1951–1952 [13]. Subsequently, WNF has been documented across the planet with the exception of Antarctica [17, 63, 72, 87, 90, 118]. …”