Co-infection of Staphylococcus aureus or Haemophilus paragallinarum exacerbates H9N2 influenza A virus infection in chickens

• Published in: Archives of virology Vol. 149; no. 11; pp. 2095 - 2104
• Main Authors: Kishida, N, Sakoda, Y, Eto, M, Sunaga, Y, Kida, H
• Format: Journal Article
• Language: English
• Published: Wien Springer 01.11.2004; New York, NY Springer Nature B.V
• Subjects: Amino acids; Animals; avian influenza; Bacterial infections; Bacteriology; Biological and medical sciences; Bird migration; Bone marrow; Chickens - microbiology; Chickens - virology; disease course; Fundamental and applied biological sciences. Psychology; Haemophilus Infections - complications; Haemophilus Infections - veterinary; Haemophilus paragallinarum; Influenza; Influenza A virus; Influenza A Virus, H9N2 Subtype; Influenza in Birds - virology; Microbiology; Miscellaneous; mixed infection; Pathogens; Poultry; Poultry Diseases - microbiology; Poultry Diseases - virology; Quarantine; Specific Pathogen-Free Organisms; Staphylococcal Infections - complications; Staphylococcal Infections - veterinary; Staphylococcus aureus; Staphylococcus infections; Veterinary medicine; Virology; Virulence; Virus Replication; Viruses; Japan; Beijing China; South Africa; China; Mixed infection; Haemophilus paragallinarum; Orthomyxoviridae; Infection; Pasteurellaceae; Virus; Vertebrata; Influenzavirus A; Influenza A virus; Viral disease; Bacteria; Micrococcales; Influenza A; Micrococcaceae; Chicken; Aves; Veterinary; Staphylococcus aureus
• ISSN: 0304-8608; 1432-8798
• DOI: 10.1007/s00705-004-0372-1

H9N2 influenza viruses are frequently isolated from chicken meat and bone marrow imported from China to Japan since 2001. These isolates were experimentally inoculated into specific pathogen-free chickens intranasally. Viruses were recovered from the meat and bone marrow of birds showing no overt signs. On the other hand, chickens co-infected with H9N2 virus and either Staphylococcus aureus or Haemophilus paragallinarum showed clinical signs severer than those shown by birds infected only with the virus alone or each of the bacteria alone. In addition, H9N2 viruses were more efficiently recovered from the chickens co-infected with S. aureus or H. paragallinarum than those from the birds infected with only the virus. The present results indicate that co-infection of H9N2 influenza virus with S. aureus or H. paragallinarum enhances the replication of the virus in chickens, resulting in exacerbation of the H9N2 virus infection.