Molecular genotyping of duck hepatitis A viruses (DHAV) in Vietnam

Abstract

Introduction: 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][2010][2011][2012][2013]. Methodology: 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.

Comparative Pathogenicity of Duck Hepatitis A Virus-1 Isolates in Experimentally Infected Pekin and Muscovy Ducklings

“…Duck hepatitis A virus-1 (DHAV-1), classified as a sole member of Picornavirus genus ( Avihepatovirus ) ( 1 ), is the most virulent virus type which can cause mortality up to 95% in ducklings younger than 3 weeks old ( 2 ). DHAV-2, isolated in Taiwan ( 3 ), and DHAV-3, isolated in South Korea ( 4 ), Vietnam, ( 5 ), and China ( 6 ), are two newly described DHV genotypes, belonging to the same genus ( Avihepatovirus) and can cause high mortalities in ducklings. Duck astrovirus type 1 (DAstV-1) and type 2 (DAstV-2 belonging to the genus ( Avastrovirus) in the family Astroviridae in addition to a member of the hepadnavirus group [duck hepatitis B virus (DHBV)] are etiologically associated with liver disease in ducks as well ( 2 ).…”

Effect of fetal calf serum on propagation of duck hepatitis A virus genotype 3 in duck embryo fibroblast cells

“…Compared with DHV-2 and DHV-3, the three DHAV genotypes can cause more severe diseases [1, 3, 12, 13]. Among the DHAV genotypes, DHAV-1 is known to be worldwide in distribution [1]; DHAV-2 has only been reported in Taiwan, China [3]; and DHAV-3 has been found in South Korea [4], mainland China [14], and Vietnam [15]. Since its first report in 2007, DHAV-3 has been known to be the most prevalent in duck industry in East and South Asia [4, 14–18].…”

Host Differences Affecting Resistance and Susceptibility of the Second Generation of a Pekin Duck Flock to Duck Hepatitis A Virus Genotype 3

“…Given that DHAV-3 is most prevalent in duck industry in East and South Asia (Fu et al, 2008; Soliman et al, 2015; Doan et al, 2016; Lin et al, 2016), the resistance breeding against DHAV-3 was started in 2014 in our laboratory by using 88 families of a Pekin duck specialized line (Z8) as a tested flock (Zhang et al, 2016). As a first step toward the resistance breeding, the authors investigated the resistance and susceptibility of Pekin duck strain Z8, a lean-type line of Pekin duck, to DHAV-3 by using experimental infections.…”