title: Highly (H5N1) and low (H7N2) pathogenic avian influenza virus infection in falcons via nasochoanal route and ingestion of experimentally infected prey.
abstract: An experimental infection with highly pathogenic avian influenza (HPAI) and low pathogenic avian influenza (LPAI) viruses was carried out on falcons in order to examine the effects of these viruses in terms of pathogenesis, viral distribution in tissues and viral shedding. The distribution pattern of influenza virus receptors was also assessed. Captive-reared gyr-saker (Falco rusticolus x Falco cherrug) hybrid falcons were challenged with a HPAI H5N1 virus (A/Great crested grebe/Basque Country/06.03249/2006) or a LPAI H7N2 virus (A/Anas plathyrhynchos/Spain/1877/2009), both via the nasochoanal route and by ingestion of previously infected specific pathogen free chicks. Infected falcons exhibited similar infection dynamics despite the different routes of exposure, demonstrating the effectiveness of in vivo feeding route. H5N1 infected falcons died, or were euthanized, between 5-7 days post-infection (dpi) after showing acute severe neurological signs. Presence of viral antigen in several tissues was confirmed by immunohistochemistry and real time RT-PCR (RRT-PCR), which were generally associated with significant microscopical lesions, mostly in the brain. Neither clinical signs, nor histopathological findings were observed in any of the H7N2 LPAI infected falcons, although all of them had seroconverted by 11 dpi. Avian receptors were strongly present in the upper respiratory tract of the falcons, in accordance with the consistent oral viral shedding detected by RRT-PCR in both H5N1 HPAI and H7N2 LPAI infected falcons. The present study demonstrates that gyr-saker hybrid falcons are highly susceptible to H5N1 HPAI virus infection, as previously observed, and that they may play a major role in the spreading of both HPAI and LPAI viruses. For the first time in raptors, natural infection by feeding on infected prey was successfully reproduced. The use of avian prey species in falconry husbandry and wildlife rehabilitation facilities could put valuable birds of prey and humans at risk and, therefore, this practice should be closely monitored.
authors.affiliation: Centre de Recerca en Sanitat Animal, Institut de Recerca i Tecnologia Agroalimentàries, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain. kateri.bertran@cresa.uab.cat
authors.forename: Kateri
authors.initials: K
authors.lastname: Bertran
authors.forename: Núria
authors.initials: N
authors.lastname: Busquets
authors.forename: Francesc Xavier
authors.initials: FX
authors.lastname: Abad
authors.forename: Jorge
authors.initials: J
authors.lastname: García de la Fuente
authors.forename: David
authors.initials: D
authors.lastname: Solanes
authors.forename: Iván
authors.initials: I
authors.lastname: Cordón
authors.forename: Taiana
authors.initials: T
authors.lastname: Costa
authors.forename: Roser
authors.initials: R
authors.lastname: Dolz
authors.forename: Natàlia
authors.initials: N
authors.lastname: Majó
mesh_terms: D000281:Administration, Intranasal / Q000662:veterinary; D000818:Animals; D004198:Disease Susceptibility / Q000662:veterinary* / Q000821:virology; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D046093:Falconiformes; D005502:Food / Q000821:virology; D007150:Immunohistochemistry / Q000662:veterinary; D053124:Influenza A Virus, H5N1 Subtype / Q000472:pathogenicity*; D057917:Influenza A Virus, H7N2 Subtype / Q000235:genetics / Q000472:pathogenicity*; D005585:Influenza in Birds / Q000473:pathology / Q000635:transmission* / Q000821:virology*; D009305:Nasopharynx / Q000821:virology; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D018709:Statistics, Nonparametric