Pathogenesis and transmissibility of highly (H7N1) and low (H7N9) pathogenic avian influenza virus infection in red-legged partridge (Alectoris rufa)

Vet Res. 2011 Feb 7;42(1):24. doi: 10.1186/1297-9716-42-24.

Abstract

An experimental infection with highly pathogenic avian influenza virus (HPAIV) and low pathogenic avian influenza virus (LPAIV) was carried out in red-legged partridges (Alectoris rufa) in order to study clinical signs, gross and microscopic lesions, and viral distribution in tissues and viral shedding. Birds were infected with a HPAIV subtype H7N1 (A/Chicken/Italy/5093/1999) and a LPAIV subtype H7N9 (A/Anas crecca/Spain/1460/2008). Uninoculated birds were included as contacts in both groups. In HPAIV infected birds, the first clinical signs were observed at 3 dpi, and mortality started at 4 dpi, reaching 100% at 8 dpi. The presence of viral antigen in tissues and viral shedding were confirmed by immunohistochemistry and quantitative real time RT-PCR (qRRT-PCR), respectively, in all birds infected with HPAIV. However, neither clinical signs nor histopathological findings were observed in LPAIV infected partridges. In addition, only short-term viral shedding together with seroconversion was detected in some LPAIV inoculated animals. The present study demonstrates that the red-legged partridge is highly susceptible to the H7N1 HPAIV strain, causing severe disease, mortality and abundant viral shedding and thus contributing to the spread of a potential local outbreak of this virus. In contrast, our results concerning H7N9 LPAIV suggest that the red-legged partridge is not a reservoir species for this virus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Viral / analysis
  • Cloaca / virology
  • Disease Susceptibility / veterinary
  • Enzyme-Linked Immunosorbent Assay / veterinary
  • Feathers / virology
  • Galliformes*
  • Influenza A Virus, H7N1 Subtype / isolation & purification
  • Influenza A Virus, H7N1 Subtype / pathogenicity*
  • Influenza A Virus, H7N9 Subtype / isolation & purification
  • Influenza A Virus, H7N9 Subtype / pathogenicity*
  • Influenza in Birds / immunology
  • Influenza in Birds / pathology
  • Influenza in Birds / transmission
  • Influenza in Birds / virology*
  • Oropharynx / virology
  • Polymerase Chain Reaction / veterinary

Substances

  • Antibodies, Viral