Further observations on serotype 2 Marek's disease virus-induced enhancement of spontaneous avian leukosis virus-like bursal lymphomas in ALVA6 transgenic chickens.

Further observations on serotype 2 Marek's disease virus-induced enhancement of spontaneous avian leukosis virus-like bursal lymphomas in ALVA6 transgenic chickens. Avian Pathol. 2014 Nov 19;:1-20 Authors: Cao W, Mays J, Kulkarni G, Dunn J, Fulton RM, Fadly A Abstract Breeders of 2009 generation of Avian Disease and Oncology Laboratory (ADOL) transgenic chicken line ALVA6, known to be resistant to infection with subgroups A and E avian leukosis virus (ALV), were vaccinated at hatch with a trivalent Marek's disease (MD) vaccine containing serotypes 1, 2, and 3 MD viruses (MDV) and were maintained under pathogen-free conditions from the day of hatch until 75 weeks of age. Spontaneous ALV-like bursal lymphomas also termed lymphoid leukosis (LL)-like lymphomas were detected in 7% of the ALVA6 breeders. There was no evidence of infection with exogenous and endogenous ALV as determined by virus isolation tests of plasma and tumor tissue homogenates. For the next three generations, serotype 2 MDV was eliminated from the trivalent MD vaccine used. Results show, for the first time, that removal of serotype 2 MDV from MD vaccines eliminated spontaneous LL-like lymphomas within 50-72 weeks of age for at least three consecutive generations. Two experiments were also conducted to determine the influence of in ovo vaccination with serotype 2 MD vaccines on enhancement of spontaneous LL-like lymphomas in ALVA6 chickens. Chickens from 2012 generatio...
Source: Avian Pathology - Category: Pathology Authors: Tags: Avian Pathol Source Type: research