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Open Access
Copyright: The authors. This article is an open access
article licensed under the terms of the Creative Commons Attribution License
(http://creativecommons.org/licenses/by/2.0) which permits unrestricted use,
distribution and reproduction in any medium, provided the work is properly
cited.
Research
2.
Contamination rate of avian Leukosis viruses among commercial
Marek's Disease vaccines in Assiut, Egypt market using reverse
transcriptase-polymerase chain reaction -
Moemen A. Mohamed, Tolba Y. Abd El-Motelib, Awad A. Ibrahim and
Moustafa E. Saif El-Deen
Vet World. 2010; 3(1): 8-12
Abstract
Avian leukosis viruses
(ALVs) in poultry may induce a
variety of deleterious effects including tumors, increased
mortalities, growth retardation and decrease in egg size and
production that led to considerable economic losses. The
identification of avian leukosis viruses
(ALVs) in imported Marek’s disease
(MD) vaccines has raised concern about transmission of these
retroviruses to vaccine recipients esp. poultry breeding stocks,
so Egypt as one of importing countries requires freedom of
infection with ALVs in
such vaccines. Subgroup specific RT-PCR was undertaken on
isolated RNA from 13 obtained commercial MD vaccines using six
pairs of primers that correspond to envelope glycoprotein gene
(gp85) which determines possible contamination with the six ALV
subgroups: A, B, C, D, E, and J. The results indicated that
RT-PCR assay for ALV-gp85 subgroup-E was positive for eight out
of thirteen (61.5%) tested MD vaccines, while primers designed
to detect subgroup A and J ALVs were
positive for five out of thirteen (38.5%)
and two out of thirteen (7.7%) respectively among examined
vaccines. No ALVs was
detected in 3/13 (23.07%) of commercially examined vaccines by
using any of six primer pairs. Finally, the using of RT-PCR
assay provides us a new, sensitive approach for identifying ALVs as
a contaminant agent that will help greatly in applying this
method for equipped labs as a quality control measure for
testing delivered MD vaccines before its administration in
poultry breeding stocks as well eradication programs through
identifying infected birds.
Key words: Marek’s disease,
vaccine contamination, avian leukosis virus,
RT-PCR
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