Child level

Same level

and two new DHV geno- (and sero-?)types (N-DHV)

Duck hepatitis virus 1 (DHV-1) is one of three small RNA viruses causing duck virus hepatitis, the other two being DHV-2 and DHV-3.

Molecular sequence data is now available to categorically or tentatively place the three serotype of duck hepatitis virus with a taxonomic framework (see also DHV-3).

Recently (30 Jun 2006), the genome sequences of three strains of DHV-1 were released on the public databases (strain 03D - DQ249299, strain H - DQ249300 & strain 5886 - DQ249301) (Tseng et al., 2007). Analysis of these sequences show them to be closely related picornaviruses, but unrelated to any members of the currently defined genera. It has therefore been proposed that they should form a novel genus within the Picornaviridae.

Partial sequences of two Chinese DHV-1 strains have also been released (26 Aug 2006), C80 (3' 4698 nt; DQ864514 - later increased to a complete genome sequence) and E63 (3' 1247 nt; DQ864515) (Ding and Zhang, unpublished). It is indicated that the latter strain is a DHV-1 variant (DHV-1v). A further partial sequence (most of the 5' UTR and beginning of VP0) of a Chinese strain of DHV-1 (A66) has been released on the public databases (DQ886445; Zhang et al., unpublished).

Two more complete DHV-1 genome sequences have been released (30 Sep 2006): strain R85952 (DQ226541) and strain DRL-62 (DQ219396) (Kim et al., 2006).

A new serotype of duck hepatitis virus has recently been described which is related to DHV-1 and has (temporarily) been named new-DHV (N-DHV) (Tseng & Tsai, 2007). The complete genome sequences will shortly be available.

 Independently workers in South Korea have described a new duck hepatitis virus serotype (Kim et al., 2007; Kim et al., unpublished). It is not yet known if the Taiwanese and Korean DHV's are serologically distinct, however, sequence differences in VP1 suggest that they may be (~28% nt difference). The new DHV's differ from DHV-1 by 32-33% in VP1.

Figure 1 (below) shows the relationships between available VP1 nt sequences of the three genotypes.

Figure 1. Mid-point rooted Neighbor-joining tree showing the relationships between the three duck hepatitis virus genotypes in the VP1 gene. They are proposed to be name duck hepatitis A virus 1 (DHAV-1), DHAV-2 and DHAV-3.

References

Ding, C. and Zhang, D. (2007). Molecular analysis of duck hepatitis virus type 1. Virology doi:10.1016/j.virol.2007.01.007.

Kim, M.-C., Kwon, Y.-K., Joh, S.-J., Lindberg, A.M., Kwon, J.-H., Kim, J.-H. and Kim, S.-J. (2006). Molecular analysis of duck hepatitis virus type 1 reveals a novel lineage close to the genus Parechovirus in the family Picornaviridae. J. Gen. Virol. 87: 3307-3316.

Kim, M.C., Kwon, Y.K., Joh, S.J., Kwon, J.H., Kim, J.H. and Kim, S.J. (2007). Development of one-step reverse transcriptase-polymerase chain reaction to detect duck hepatitis virus type 1. Avian Dis. 51: 540-545.

Kim, M.C., Kwon, Y.K. and Joh, S.J. Recent Korean isolates of duck hepatitis virus reveal the presence of a new geno- and serotype comparing to duck hepatitis virus type 1. Unpublished. [Avian Disease Division, Nvqrs, 480, Anyang 6 Dong, Manan-Gu, Anyang, Geyonggi 430-824, Republic of Korea]

Tseng, C.-H. and Tsai, H.-J., (2007). Molecular characterization of a new serotype of duck hepatitis virus, Virus Res. 126: 19-31.

Tseng, C.H., Knowles, N.J. and Tsai, H.J. (2007). Molecular analysis of type 1 duck hepatitis virus indicated that it should be assigned to a new genus. Virus Research 123: 190-203.

Zhang, X.F., Zhao, R.H. and Wen, L.B. Unpublished [Veterinary Science, Jiangsu Academy of Agricultural Sciences, Zhong Ling Street 50, Nan Jing, Jiangsu 210014, China].