Novel sequences of subgroup J avian leukosis viruses associated with hemangioma in Chinese layer hens.

Background: Avian leukosis virus subgroup J (ALV-J) preferentially induces myeloid leukosis (ML) in meat-type birds. Since 2008, many clinical cases of hemangioma rather than ML have frequently been reported in association with ALV-J infection in Chinese layer flocks.

Results: Three ALV-J strains associated with hemangioma were isolated and their proviral genomic sequences were determined.

Genetic diversity and phylogenetic analysis of glycoprotein GP85 of ALV-J isolates from Mainland China between 1999 and 2010: coexistence of two extremely different subgroups in layers.

Avian leukosis virus subgroup J (ALV-J), first isolated in 1989, preferentially infects meat-type birds. However, layer flocks in China have experienced outbreaks of this virus since 2008. To understand the genetic diversity of ALV-J in Chinese layers, we compared and analyzed the GP85 gene sequences of 106 ALV-J isolates that were isolated between 1999 and 2010 in Mainland China.

Molecular characteristics of segment B of seven very virulent infectious bursal disease viruses isolated in China.

Infectious bursal disease virus (IBDV) is a birnavirus that causes immunosuppressive disease in chickens. Segment B of IBDV encodes the RNA-dependent RNA polymerase VP1, which is involved in virulence. We sequenced and analyzed segment B from seven Chinese IBDV isolates, all belonging to very virulent IBDV (vvIBDV), and clustered into Branches II and III.