title: Pathology and viral antigen distribution of lethal pneumonia in domestic cats due to pandemic (H1N1) 2009 influenza A virus.
abstract: A novel swine-origin H1N1 influenza A virus has been identified as the cause of the 2009 influenza pandemic in humans. Since then, infections with the pandemic (H1N1) 2009 influenza virus have been documented in a number of animal species. The first known cases of lethal respiratory disease associated with pandemic (H1N1) 2009 influenza virus infection in house pets occurred in domestic cats in Oregon. A 10-year-old neutered domestic shorthair and an 8-year-old spayed domestic shorthair died shortly after developing severe respiratory disease. Grossly, lung lobes of both cats were diffusely firm and incompletely collapsed. Histologically, moderate to severe necrotizing to pyonecrotizing bronchointerstitial pneumonia was accompanied by serofibrinous exudation and hyaline membranes in the alveolar spaces. Influenza A virus was isolated from nasal secretions of the male cat and from lung homogenate of the female cat. Both isolates were confirmed as pandemic (H1N1) 2009 influenza virus by real-time reverse transcriptase polymerase chain reaction. With immunohistochemistry, influenza A viral antigen was demonstrated in bronchiolar epithelial cells, pneumocytes, and alveolar macrophages in pneumonic areas. The most likely sources of infection were people in the household with influenza-like illness or confirmed pandemic (H1N1) 2009 influenza. The 2 cases reported here provide, to the best of the authors' knowledge, the first description of the pathology and viral antigen distribution of lethal respiratory disease in domestic cats after natural pandemic (H1N1) 2009 influenza virus infection, probably transmitted from humans.
authors.affiliation: Veterinary Diagnostic Laboratory and Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Magruder Hall Room 105, Corvallis, OR 97339-0429, USA. christiane.loehr@oregonstate.edu
authors.forename: C V
authors.initials: CV
authors.lastname: Löhr
authors.forename: E E
authors.initials: EE
authors.lastname: DeBess
authors.forename: R J
authors.initials: RJ
authors.lastname: Baker
authors.forename: S L
authors.initials: SL
authors.lastname: Hiett
authors.forename: K A
authors.initials: KA
authors.lastname: Hoffman
authors.forename: V J
authors.initials: VJ
authors.lastname: Murdoch
authors.forename: K A
authors.initials: KA
authors.lastname: Fischer
authors.forename: D M
authors.initials: DM
authors.lastname: Mulrooney
authors.forename: R L
authors.initials: RL
authors.lastname: Selman
authors.forename: W M
authors.initials: WM
authors.lastname: Hammill-Black
mesh_terms: D000818:Animals; D000956:Antigens, Viral / Q000032:analysis*; D002371:Cat Diseases / Q000276:immunology* / Q000473:pathology; D002415:Cats; D004196:Disease Outbreaks / Q000662:veterinary; D017809:Fatal Outcome; D005260:Female; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D008168:Lung / Q000473:pathology / Q000821:virology; D008297:Male; D009922:Oregon; D009976:Orthomyxoviridae Infections / Q000276:immunology / Q000473:pathology / Q000662:veterinary*; D011024:Pneumonia, Viral / Q000276:immunology / Q000473:pathology / Q000662:veterinary*
chemical_list: D000956:Antigens, Viral
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