Isolation and genetic characterization of H5N2 influenza viruses from pigs in Korea.
Due to dual susceptibility to both human and avian influenza A viruses, pigs are believed to be effective intermediate hosts for the spread and production of new viruses with pandemic potential. In early 2008, two swine H5N2 viruses were isolated from our routine swine surveillance in Korea. The sequencing and phylogenetic analysis of surface proteins revealed that the Sw/Korea/C12/08 and Sw/Korea/C13/08 viruses were derived from avian influenza viruses of the Eurasian lineage. However, although the Sw/Korea/C12/08 isolate is an entirely avian-like virus, the Sw/Korea/C13/08 isolate is an avian-swine-like reassortant with the PB2, PA, NP, and M genes coming from a 2006 Korean swine H3N1-like virus. The molecular characterization of the two viruses indicated an absence of significant mutations that could be associated with virulence or binding affinity. However, animal experiments showed that the reassortant Sw/Korea/C13/08 virus was more adapted and was more readily transmitted than the purely avian-like virus in a swine experimental model but not in ferrets. Furthermore, seroprevalence in swine sera from 2006 to 2008 suggested that avian H5 viruses have been infecting swine since 2006. Although there are no known potential clinical implications of the avian-swine reassortant virus for pathogenicity in pigs or other species, including humans, at present, the efficient transmissibility of the swine-adapted H5N2 virus could facilitate virus spread and could be a potential model for pandemic, highly pathogenic avian influenza (e.g., H5N1 and H7N7) virus outbreaks or a pandemic strain itself.
College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, Republic of Korea.
Jun Han
JH
Lee
Philippe Noriel Q
PN
Pascua
Min-Suk
MS
Song
Yun Hee
YH
Baek
Chul-Joong
CJ
Kim
Hwan-Woon
HW
Choi
Moon-Hee
MH
Sung
Richard J
RJ
Webby
Robert G
RG
Webster
Haryoung
H
Poo
Young Ki
YK
Choi
D000595:Amino Acid Sequence; D000818:Animals; D000956:Antigens, Viral / Q000276:immunology; D005289:Ferrets; D053125:Influenza A Virus, H5N2 Subtype / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification*; D007723:Korea; D009976:Orthomyxoviridae Infections / Q000097:blood / Q000473:pathology / Q000662:veterinary* / Q000821:virology*; D010802:Phylogeny; D017385:Sequence Homology; D013552:Swine / Q000097:blood / Q000276:immunology / Q000821:virology*; D013553:Swine Diseases / Q000097:blood / Q000276:immunology / Q000473:pathology / Q000821:virology*; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
D000956:Antigens, Viral; D014764:Viral Proteins