title: Susceptibility of pigeons to clade 1 and 2.2 high pathogenicity avian influenza H5N1 virus.
abstract: To assess the susceptibility of pigeons (Columba livia) to infection with H5N1 high pathogenicity avian influenza virus (HPAIV), four groups of 1-yr-old and 4-wk-old racing pigeons (10 birds in each group) were inoculated oculonasally with 106 50% egg infectious dose (EID50) of A/crested eagle/Belgium/01/2004 (clade 1) or A/swan/Poland/305-135V08/2006 (clade 2.2). Contact specific-pathogen-free (SPF) chickens were kept in the same isolators as young pigeons (two chickens per group). At 3, 5, 7, 10, and 14 days postinfection (PI) two pigeons from each infected group were selected randomly, and oropharyngeal and cloacal swabs (pigeons and contact chickens) as well as a number of internal organs (pigeons) were collected for viral RNA detection in real-time reverse transcription PCR (RRT-PCR) and histopathology. At the end of the experiment (14 days PI) blood samples from two pigeons in each group and from contact SPF chickens were also collected, and sera were tested using hemagglutination inhibition (HI) test and blocking enzyme-linked immunosorbent assay (bELISA). During the observation period all pigeons remained clinically healthy, and no gross lesions were observed in any of the infected groups. SPF contact chickens were also healthy and negative in RRT-PCR and HI tests. However, the clade 1 H5N1 virus produced more sustained infection manifested by the presence of histopathologic changes (consisting mainly of mild to moderate hemorrhagic and inflammatory lesions), prolonged persistence of viral RNA (detectable between 3 and 10 days PI) in a variety of tissues of both adult and juvenile birds (with highest RNA load in lungs and brain) as well as slight viral shedding from the trachea and cloaca, but without transmission to SPF contact chickens. Additionally, two clade 1-infected adult pigeons sacrificed at the end of experiment showed seroconversion in bELISA and HI test (using homologous virus as antigen). The viral RNA was found only at day 3 PI in one adult pigeon inoculated with dade 2.2 H5N1 virus, but neither microscopic lesions nor seroconversion were found in any other tested birds inoculated with A/swan/Poland/305-135V08/2006. Our results support the observations that pigeons are resistant to H5N1 HPAIV (no deaths or clinical signs), but there may be clade-dependent differences in the pathogenic potentials of H5N1 HPAIV of Asian origin.
authors.affiliation: National Reference Laboratory for Avian influenza and Newcastle Disease, Department of Poultry Diseases, National Veterinary Research Institute, Al. Partyzantów 57, 24-100 Pulawy, Poland. ksmiet@piwet.pulawy.pl
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Smietanka
authors.forename: Zenon
authors.initials: Z
authors.lastname: Minta
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Wyrostek
authors.forename: Michal
authors.initials: M
authors.lastname: Jóźwiak
authors.forename: Monika
authors.initials: M
authors.lastname: Olszewska
authors.forename: A Katarzyna
authors.initials: AK
authors.lastname: Domańska-Blicharz
authors.forename: A Michał
authors.initials: AM
authors.lastname: Reichert
authors.forename: Anna
authors.initials: A
authors.lastname: Pikuła
authors.forename: Adelite
authors.initials: A
authors.lastname: Habyarimana
authors.forename: Thierry
authors.initials: T
authors.lastname: van den Berg
mesh_terms: D000818:Animals; D001921:Brain / Q000473:pathology / Q000821:virology; D010856:Columbidae; D004198:Disease Susceptibility; D053124:Influenza A Virus, H5N1 Subtype; D005585:Influenza in Birds / Q000276:immunology / Q000821:virology*; D008099:Liver / Q000473:pathology / Q000821:virology; D008168:Lung / Q000473:pathology / Q000821:virology; D012367:RNA, Viral / Q000235:genetics / Q000302:isolation & purification; D013154:Spleen / Q000473:pathology / Q000821:virology; D014132:Trachea / Q000473:pathology / Q000821:virology
chemical_list: D012367:RNA, Viral