Genetic evolution of H5 highly pathogenic avian influenza virus in domestic poultry in Vietnam between 2011 and 2013.
In spite of highly pathogenic avian influenza H5N1 vaccination campaigns for domestic poultry, H5N1 viruses continue to circulate in Vietnam. To estimate the prevalence of avian influenza virus in Vietnam, surveillance was conducted between November 2011 and February 2013. Genetic analysis of 312 highly pathogenic avian influenza H5 viruses isolated from poultry in Vietnam was conducted and possible genetic relationships with strains from neighboring countries were investigated. As previously reported, phylogenetic analysis of the avian influenza virus revealed two H5N1 HPAI clades that were circulating in Vietnam. Clade 1.1, related to Cambodian strains, was predominant in the southern provinces, while clade 2.3.2.1 viruses were predominant in the northern and central provinces. Sequence analysis revealed evidence of active genetic evolution. In the gene constellation of clade 2.3.2.1, genotypes A, B, and B(II) existed during the 2011/2012 winter season. In June 2012, new genotype C emerged by reassortment between genotype A and genotype B(II), and this genotype was predominant in 2013 in the northern and central provinces. Interestingly, enzootic Vietnamese clade 2.3.2.1C H5 virus subsequently reassorted with N2, which originated from wild birds, to generate H5N2 highly pathogenic avian influenza, which was isolated from duck in the northeast region. This investigation indicated that H5N1 outbreaks persist in Vietnam and cause genetic reassortment with circulating viruses. It is necessary to strengthen active influenza surveillance to eradicate highly pathogenic avian influenza viruses and sever the link between highly pathogenic avian influenza and other circulating influenza viruses.
Animal and Plant Quarantine Agency, 175 Anyangro, Manan, Anyang, Gyeonggi, 430-757, Republic of Korea.
Eun-Kyoung
EK
Lee
Animal and Plant Quarantine Agency, 175 Anyangro, Manan, Anyang, Gyeonggi, 430-757, Republic of Korea.
Hyun-Mi
HM
Kang
Animal and Plant Quarantine Agency, 175 Anyangro, Manan, Anyang, Gyeonggi, 430-757, Republic of Korea.
Kwang-Il
KI
Kim
Animal and Plant Quarantine Agency, 175 Anyangro, Manan, Anyang, Gyeonggi, 430-757, Republic of Korea.
Jun-Gu
JG
Choi
National Center for Veterinary Diagnosis, Department of Animal Health, 11/78 Giai Phong St. Dong Da disk Hanoi, Vietnam.
Thanh Long
TL
To
National Center for Veterinary Diagnosis, Department of Animal Health, 11/78 Giai Phong St. Dong Da disk Hanoi, Vietnam.
Tho Dang
TD
Nguyen
Animal and Plant Quarantine Agency, 175 Anyangro, Manan, Anyang, Gyeonggi, 430-757, Republic of Korea.
Byung-Min
BM
Song
Animal and Plant Quarantine Agency, 175 Anyangro, Manan, Anyang, Gyeonggi, 430-757, Republic of Korea.
Jipseol
J
Jeong
Animal and Plant Quarantine Agency, 175 Anyangro, Manan, Anyang, Gyeonggi, 430-757, Republic of Korea.
Kang-Seuk
KS
Choi
Animal and Plant Quarantine Agency, 175 Anyangro, Manan, Anyang, Gyeonggi, 430-757, Republic of Korea.
Ji-Ye
JY
Kim
Animal and Plant Quarantine Agency, 175 Anyangro, Manan, Anyang, Gyeonggi, 430-757, Republic of Korea.
Hee-Soo
HS
Lee
Animal and Plant Quarantine Agency, 175 Anyangro, Manan, Anyang, Gyeonggi, 430-757, Republic of Korea leeyj700@korea.kr kimhong@snu.ac.kr.
Youn-Jeong
YJ
Lee
College of Veterinary Medicine, Seoul National University, 599 Gwanakro, Seoul, 151-742, Republic of Korea leeyj700@korea.kr kimhong@snu.ac.kr.
Jae-Hong
JH
Kim
D000818:Animals; D019143:Evolution, Molecular; D005838:Genotype; D009980:Influenza A virus / Q000235:genetics*; D005585:Influenza in Birds / Q000453:epidemiology* / Q000821:virology; D008969:Molecular Sequence Data; D010802:Phylogeny; D011200:Poultry; D017422:Sequence Analysis, DNA / Q000662:veterinary; D014744:Vietnam / Q000453:epidemiology
Vietnam; avian influenza virus; domestic poultry; genetic reassortment