Surveillance and characterization of low pathogenic H5 avian influenza viruses isolated from wild migratory birds in Korea.
Migratory waterfowls are the natural reservoir of influenza A viruses. However, interspecies transmission had occasionally caused outbreaks in various hosts including humans. To characterize the genetic origins of H5 avian influenza viruses isolated from migratory birds in South Korea, phylogenetic analysis were conducted. A total of 53 H5 viruses were isolated between October 2005 and November 2008. Full genetic characterization indicated that most of these viruses belong to the Eurasian-like avian lineage. However, some segments of the AB/Korea/W235/07 and the AB/Korea/W236/07 isolates were clustered with North American lineage viruses rather than those of the Eurasian lineage, suggesting the occurrence of reassortment between these two avian virus lineages. Phylogenetic analysis further demonstrated that the H5N2 and H5N3 virus isolates were of the low pathogenicity H5 phenotype. The H5 viruses appear to be antigenically similar to each other, but could be distinguished from a recent HPAI H5N1 (EM/Korea/W149/06) virus by hemagglutinin inhibition (HI) assays. Experimental inoculation of representative viruses indicated that certain isolates, particularly AB/Korea/W163/07 (H5N2), could be detected in trachea and lungs of chickens but none could be transmitted by direct contact. Furthermore, all of the viruses could be detected in mice lung without prior adaptation which is indicative of their pathogenic potential in a mammalian host. Overall, our results emphasize the important role that migratory birds play in the perpetuation, transport, and reassortment of avian influenza viruses stressing the need for continued surveillance of influenza virus activity in these avian populations.
Baek
Yun Hee
YH
College of Medicine and Medical Research Institute, Chungbuk National University, 12 Gaeshin-Dong, Heungduk-Ku, Cheongju 361-763, Republic of Korea.
Pascua
Philippe Noriel Q
PN
Song
Min-Suk
MS
Park
Kuk Jin
KJ
Kwon
Hyeok-il
HI
Lee
Jun Han
JH
Kim
Seok-Yong
SY
Moon
Ho-Jin
HJ
Kim
Chul-Joong
CJ
Choi
Young Ki
YK
D000818:Animals; D001715:Bird Diseases / Q000453:epidemiology* / Q000821:virology*; D001717:Birds; D002645:Chickens / Q000821:virology; D016000:Cluster Analysis; D004195:Disease Models, Animal; D018562:Disease Transmission, Infectious; D006385:Hemagglutination Inhibition Tests; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000032:analysis*; D009980:Influenza A virus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D005585:Influenza in Birds / Q000453:epidemiology* / Q000821:virology*; D007723:Korea / Q000453:epidemiology; D008168:Lung / Q000821:virology; D008969:Molecular Sequence Data; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics; D016865:Reassortant Viruses; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D012703:Serotyping; D014132:Trachea / Q000821:virology
D019267:Hemagglutinin Glycoproteins, Influenza Virus; D012367:RNA, Viral; C109963:hemagglutinin, avian influenza A virus