DUCK HEPATITIS VIRUS TYPE 1 ISOLATED FROM DUCKS SUFFERED FROM DUCK ASCITES SYNDROME

In April 2011,a duck ascites syndrome was found in 20-45 day-old Cherry Valley ducks in some duck farm of Hebei province.This disease was characterized by the abdominal cavity filled with a clear,dark brown or beer-like ascites.Two virus isolates named HB01 and HB02 were isolated from duck liver samples which were from two different day-age ducks.This two virus isolates had no hemagglutinating activity with chicken,duck and goose red blood cells.RT-PCR or PCR results showed that Duck hepatitis virus type 1 could be detected in HB01 and HB02,but other eight kinds of duck virus not.Four out of ten ducks died within one week postinoculation when 5 day-old SPF ducks were challenged with HB02,while no ducks died in 20 day-old SPF ducks group.Phylogenetic and evolutionary analysis revealed that HB02 had a close relationship with NA,C80 and FC64 strains based on the alignment of the full genome sequence of different strains.According to the above results,we deduced that duck hepatitis virus(including some vaccine virus) could be one of the important factors to induce duck ascites syndrome occurred in some duck farms of Hebei Prorince this year.