Development and evaluation of an inactivated bivalent vaccine against duck viral hepatitis / 生物工程学报

The rapid mutation and widely spread of duck hepatitis A virus (DHAV) lead to the vast economic loss of the duck industry. To prepare and evaluate bivalent inactivated vaccine laboratory products of DHAV, 6 strains were screened from 201 DHAV-1 strains and 38 DHAV-3 strains by using serotype epidemiological analysis in most of the duck factory. Vaccine candidate strains were selected by ELD50 and LD50 tests in the 6 strains. Continuously passaged, the 5th passaged duck embryos bodies grinding fluid was selected as vaccine virus seeds. The virus seeds were treated with formaldehyde and water in oil in water (W/O/W) emulsions, making into three batches of two bivalent inactivated vaccine laboratory products. The safety test, antibody neutralization test, challenged protection and cross immune protection experiment suggested that the vaccines possessed good safety, and neutralizing antibodies were detected at 7th day and the challenged protection rate reached 90% to 100% at the 14th and 21st day. Moreover, immune duration of ducklings lasted more than five weeks. However, cross-immunity protection experiments with DHAV-SH and DHAV-FS only had 20%-30%. The two bivalent inactivated vaccine laboratory products of duck viral hepatitis were effective and reliable, providing a new method as well as a new product for DHAV prevention and control.

Sequence analysis of VP1 gene of the duck hepatitis A virus type 3 strains isolated from Shandong Province of China in 2012 / 病毒学报

To reveal the genetic variation of the viral protein 1 (VP1) gene of the duck hepatitis A virus type 3 (DHAV-3), the VP1 gene of 13 virulent DHAV-3 strains isolated from Shandong province of China in 2012 were amplified by RT-PCR, sequenced and analyzed. The results showed that all the VP1 genes of the 13 isolates contained 720 nucleotides encoding 240 amino acids, and shared with nucleotide identities of 94. 6%-99.9% and amino acid identities of 95.0%-100%. The nucleotide and amino acid sequence homologies between the 13 DHAV-3 isolates and other 31 DHAV-3 reference strains were 92.5%-100% and 90. 8%-100%, respectively. Phylogenetic analysis showed that the VP1 gene of DHAV-3 had distinct geographical characteristics. Distribution of genotypes of the 44 DHAV-3 strains was as follows: except the vaccine strain B63, all the other Chinese isolates belonged to genotype I (GI), Vietnamese wild isolates mainly belonged to subtype 1 (S1) of genotype II (GII), and all Korean isolates belonged to subtype 2 (S2) of GII.

Overview on duck virus hepatitis A / 生物工程学报

This article describes the nomenclature, history and genetic evolution of duck hepatitis A virus, and updates the epidemiology, clinical symptom and surveillances of duck virus hepatitis A. It also summarizes the present status and progress of duck virus hepatitis A and illustrated the necessity and urgency of its research, which provides rationale for the control of duck hepatitis A virus disease in China.

Molecular cloning and analysis of the 3' terminal sequence of duck hepatitis virus genome / 病毒学报

The authentic 3' terminal sequences of genomes of duck hepatitis virus (DHV) serotype I strain C80 and serotype I variant strain E63 were obtained by using 3' RACE and RT-PCR techniques. The analysis showed that 3' terminal sequences in the genomes of the two DHV strains include the 3D region of 1359 nucleotides (nt), the terminator codon TGA, and 3'untranslated region (UTR) of 314 nt. The poly (A) tails of C80 and E63 are 18 nt and 19 nt in length respectively. The deduced 3D proteins of 453 amino acids of both DHV strains contain the motifs KDELR, DxxxxD, GxxCSGxxxTxxxNS, YGDD, and FLKR characteristic for RNA polymerase of picornaviruses, which confirms DHV serotype I to be a member of Picornaviridae . The amino acid sequence identities among 3D protein of the two DHV strains with representatives of nine other picornavirus genera range from 16% to 37%, which are within the value ranges (18%-60%) of 3D amino acid sequence identities obtained from inter-genera comparisons. In addition, DHV serotype I possesses the longest 3'UTR in the family Picornaviridae. Phylogenetic analysis of 3D proteins indicated that DHV serotype I may belong to a separated genus of the family Picornaviridae.

Preparation and evaluation of combined inactivated aluminium hydroxide gel vaccine against duck virus hepatitis and duck plague diseases private

A combined bivalent alhydragel vaccine against both duck plague virus [DPV] and duck virus hepatitis [DVH] was prepared. The efficacy of the new vaccine was evaluated in different groups of ducklings compared with a single vaccine against each virus alone. Evaluation depended upon estimation of both humoral and cellular immune response. The prepared combined vaccine offered a high titre against each virus. Obtained results have shown that the antibody titre obtained with the new vaccine are never inferior to the titres obtained with the separate single vaccine

Sequence analysis of cloned duck hepatitis B virus genome from a Chongqing brown duck / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To clone and analyze duck hepatitis B virus genome from Chongqing brown duck.</p><p><b>METHODS</b>Duck hepatitis B virus (DHBV) DNA extracted from a Chongqing brown duck was amplified by PCR and cloned into PGEM-T vector using T-A clone method. The sequence of this DHBV genome was analyzed with some softwares after identified.</p><p><b>RESULTS</b>The duck hepatitis B virus genome from Chongqing brown duck (DHBVcq), which was 3 024 nucleotides long, contained three ORFs whose onset and end nucleotides were in accord with those of HPUGA, encoding P, PreC/C and PreS/S protein respectively. Comparison of this strain with other DHBV reported in GenBank showed that the homology of DHBVcq and M32990 got the highest score of 94.9% at nucleotide level, while DHBVcq and DHBVCG got the least (89.8%). Most of the conserved regulation nucleotides and amino acids sequence found in other DHBV were also identified in DHBVcq. The epsilon region of DHBVcq, which was important for encapsidation of pgRNA and synthesis of minus-strand DNA, differed from that of most other DHBV strains, forming a stem-loop conformation with a three- nucleotides upper stem rather than a common nine-nucleotides one in free status.</p><p><b>CONCLUSION</b>The successful clone and analysis of DHBVcq provide further studies with helpful information.</p>