Highly (H5N1) and low (H7N2) pathogenic avian influenza virus infection in falcons

Researchers of CReSA have demonstrated that gyr-saker hybrid falcons are highly susceptible to H5N1 highly pathogenic avian influenza (HPAI) virus infection, and that they may play a major role in the spreading of both HPAI and pathogenic avian influenza (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.

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 or a LPAI H7N2 virus, both via the nasochoanal route and by ingestion of previously infected specific pathogen free chicks. Main conclusions of this work are:

  • 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.

Falconry is an ancient tradition in the Arabian Peninsula that has spread worldwide, resulting in a strong trade of all species of falcons around the world. Nowadays, falconry is most popular in European countries such as The United Kingdom, Germany and Spain, in that order. It is well known that migration of infected wild birds is one of the mechanisms in the spreading of AI viruses, thus many falcon species may contribute to the movement of both HPAI and LPAI viruses within, or between countries.

This work has been published in: Bertran K, Busquets N, Abad FX, García de la Fuente J, Solanes D, Cordón I, Costa T, Dolz R, Majó N. Highly (H5N1) and low (H7N2) pathogenic avian influenza virus infection in falcons via nasochoanal route and ingestion of experimentally infected prey. PLoS One. 2012;7(3):e32107.

Download the full paper (PubMed): http://www.ncbi.nlm.nih.gov/pubmed/22427819

To contact the coordinator of the research line “Pathogenesis, diagnosis, epidemiology and control of avian viral infections”:

Natàlia Majó i Masferrer
Email: natalia.majo@cresa.uab.cat
Phone no.: +34 935814563
Fax: +34 935814490
Edifici CReSA. Campus UAB
08193 Bellaterra (Barcelona) Spain

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