Isolation and characterization of a novel H9N2 influenza virus in Korean native chicken farm.
An outbreak of avian influenza, caused by an H9N2 low-pathogenic avian influenza virus (AIV), occurred in a chicken farm and caused severe economic losses due to mortality and diarrhea. AIV was isolated and identified in a sample from an affected native Korean chicken. Genetic analysis of the isolate revealed a high sequence similarity to genes of novel reassortant H9N2 viruses isolated from slaughterhouses and live bird markets in Korea in 2008 and 2009. Animal challenge studies demonstrated that the replication kinetics and pathogenicity of the isolate were considerably altered due to adaptation in chickens. Vaccine protection studies indicated that commercial vaccine was not able to prevent virus shedding and clinical disease when chickens were challenged with the isolate. These results suggest that the novel H9N2 virus possesses the capacity to replicate efficiently in the respiratory system against vaccination and to cause severe disease in domestic chickens. The results also highlight the importance of appropriate updating of vaccine strains, based on continuous surveillance data, to prevent the possibility of a new H9N2 epidemic in Korea.
Avian Disease Laboratory, College of Veterinary Medicine, Konkuk University, Seoul, 143-701, Korea
Yu-Na
YN
Lee
Dong-Hun
DH
Lee
Jae-Keun
JK
Park
Tae-Hyun
TH
Lim
Ha-Na
HN
Youn
Seong-Su
SS
Yuk
Youn-Jeong
YJ
Lee
In-phil
IP
Mo
Haan-Woo
HW
Sung
Joong-Bok
JB
Lee
Seung-Yong
SY
Park
In-Soo
IS
Choi
Chang-Seon
CS
Song
D000818:Animals; D002645:Chickens; D004196:Disease Outbreaks / Q000662:veterinary; D053127:Influenza A Virus, H9N2 Subtype / Q000235:genetics / Q000302:isolation & purification*; D007252:Influenza Vaccines / Q000276:immunology; D005585:Influenza in Birds / Q000453:epidemiology / Q000517:prevention & control / Q000821:virology*; D056910:Republic of Korea / Q000453:epidemiology
D007252:Influenza Vaccines