Characterization of H9N2 influenza viruses isolated from vaccinated flocks in an integrated broiler chicken operation in eastern China during a 5 year period (1998-2002).
In the current study, we characterized H9N2 influenza viruses isolated from vaccinated flocks in an integrated broiler chicken operation during a 5 year period (1998-2002). Phylogenetic analysis of the 8 genes of 11 representative viruses showed that they all shared high similarity to that of the first isolate, A/Chicken/Shanghai/F/1998 (Ck/SH/F/98), and clustered to the same lineages. Furthermore, all 11 viruses had a 9 nt deletion between positions 206 and 214 of the neuraminidase gene. These genetic characteristics strongly suggest that these viruses are descendants of the first isolate. In addition, our study also showed that the H9N2 viruses circulating in the operation during this 5 year period were evolving, as shown by antigenic variations between viruses manifested by reactivity with polyclonal antisera and monoclonal antibodies, by haemagglutination with erythrocytes from different animals, by amino acid differences in haemagglutinin and neuraminidase proteins, and by variation in their ability to replicate in the respiratory and intestinal tract and to be transmitted by aerosol. Phylogenetic analysis revealed that the internal genes from some H5N1 viruses of duck origin clustered together with those from H9N2 virus and that the RNP genes of these H5N1 viruses isolated after 2001 are more closely related to the genes of the Ck/SH/F/98-like H9N2 viruses, indicating more recent reassortment events between these two subtypes of viruses. Continuous surveillance of influenza virus in poultry and waterfowl is critical for monitoring the genesis and emergence of potentially pandemic strains in this region.
Zhang
Pinghu
P
Jiangsu Center for Drug Screening, China Pharmaceutical University, Nanjing 210038, PR China.|Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, PR China.
Tang
Yinghua
Y
Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, PR China.
Liu
Xiaowen
X
Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, PR China.
Peng
Daxin
D
Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, PR China.
Liu
Wenbo
W
Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, PR China.
Liu
Hongqi
H
Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, PR China.
Lu
Shan
S
Laboratory of Nucleic Acid Vaccines, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.|China-US Vaccine Research Center, the First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, PR China.
Liu
Xiufan
X
Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, PR China.
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D000940:Antigenic Variation; D002645:Chickens; D002681:China; D053124:Influenza A Virus, H5N1 Subtype / Q000235:genetics / Q000302:isolation & purification; D053127:Influenza A Virus, H9N2 Subtype / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000235:genetics / Q000276:immunology; D005585:Influenza in Birds / Q000517:prevention & control / Q000821:virology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011201:Poultry Diseases / Q000517:prevention & control / Q000821:virology*; D017422:Sequence Analysis, DNA; D014611:Vaccination / Q000662:veterinary; D014764:Viral Proteins / Q000235:genetics
D000914:Antibodies, Viral; D007252:Influenza Vaccines; D014764:Viral Proteins