Molecular genotyping of duck hepatitis A viruses (DHAV) in Vietnam.
BACKGROUND
The aim of this study was to identify the genetic characteristics and molecular genotyping of duck hepatitis A virus (DHAV) isolated in Vietnam during 2009-2013.


METHODS
Thirty duckling livers from outbreaks between 2009 and 2013 in seven provinces were collected and identified by polymerase chain reaction (PCR). Then, VP1 genes of eleven positive samples and two attenuated vaccine strains were sequenced and analyzed.


RESULTS
Genotypic and phylogenetic analyses indicated that the 13 Vietnamese isolates were classified into two genotypes, DHAV-1 and DHAV-3. The rate of identity and homology was 91%-100% between the 10 Vietnamese and 26 global strains of DHAV-3, and 92%-100% between 3 Vietnamese and 16 strains of DHAV-1. Between the DHAV-3 and DHAV-1 strains, the divergence reached 30%. At the C-terminal of VP1 for the different strains, a hypervariable region was observed, and notably, six of the Vietnamese DHAV-3 strains in this study showed four consistent differences (at positions T184M, Q200H, K207N, and K214R) within this group that were distinct from all other DHAV-3 strains.


CONCLUSIONS
This is the first report of molecular characterization of DHAVs in Vietnam. At least two genotypes were identified, DHAV-1 and DHAV-3, with diversified clades within and between genotypes. DHAV-3 seemed to be dominant in Vietnam.
Institute of Biotechnology, Vietnam Academy of Science and Technology, Hanoi, Vietnam. doantthuong74@gmail.com.
Huong Thi Thanh
HT
Doan
Xuyen Thi Kim
XT
Le
Roan Thi
RT
Do
Chau Thi Minh
CT
Hoang
Khue Thi
KT
Nguyen
Thanh Hoa
TH
Le
D000818:Animals; D016000:Cluster Analysis; D004372:Ducks / Q000821:virology*; D014644:Genetic Variation; D005838:Genotype; D060005:Genotyping Techniques; D030041:Hepatitis A virus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D006524:Hepatitis, Viral, Animal / Q000821:virology*; D010802:Phylogeny; D014744:Vietnam; D015678:Viral Structural Proteins / Q000235:genetics
C096539:VP1 protein, hepatitis A virus; D015678:Viral Structural Proteins