Molecular epidemiology of Newcastle disease viruses in Vietnam.
Newcastle disease virus (NDV) causes significant economic losses to the poultry industry in Southeast Asia. In the present study, 12 field isolates of NDV were recovered from dead village chickens in Vietnam between 2007 and 2012, and were characterized. All the field isolates were classified as velogenic. Based on the sequence analysis of the F variable region, two distinct genetic groups (Vietnam genetic groups G1 and G2) were recognized. Phylogenetic analysis revealed that all the 12 field isolates fell into the class II genotype VII cluster. Ten of the field isolates, classified as Vietnam genetic group G1, were closely related to VIIh viruses that had been isolated from Indonesia, Malaysia, and Cambodia since the mid-2000s, while the other two field isolates, of Vietnam genetic group G2, clustered with VIId viruses, which were predominantly circulating in China and Far East Asia. Our results indicate that genotype VII viruses, especially VIIh viruses, are predominantly responsible for the recent epizootic of the disease in Vietnam.
Avian Diseases Division, Animal and Plant Quarantine Agency, 175 Anyang-ro, Manan-gu, Anyang, Gyeonggi, 430-757, Republic of Korea, kchoi0608@korea.kr.
Kang-Seuk
KS
Choi
Soo-Jeong
SJ
Kye
Ji-Ye
JY
Kim
Thanh Long
TL
To
Dang Tho
DT
Nguyen
Youn-Jeong
YJ
Lee
Jun-Gu
JG
Choi
Hyun-Mi
HM
Kang
Kwang-Il
KI
Kim
Byung-Min
BM
Song
Hee-Soo
HS
Lee
D000595:Amino Acid Sequence; D000818:Animals; D002645:Chickens / Q000235:genetics; D015967:Gene Expression Regulation, Viral / Q000502:physiology; D005838:Genotype; D008296:Malaysia; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D009521:Newcastle Disease / Q000453:epidemiology* / Q000821:virology; D009522:Newcastle disease virus / Q000145:classification / Q000235:genetics*; D010802:Phylogeny; D011200:Poultry / Q000235:genetics; D011201:Poultry Diseases / Q000453:epidemiology* / Q000821:virology; D014744:Vietnam / Q000453:epidemiology