RNA was extracted from 13 MD vaccines then
examined with RT-PCR using specific primers that
have the ability to amplify all subgroups of ALVs. Table
2 presents results of testing thirteen obtained
commercial MD vaccines using RT-PCR
Primer set E-F and E-R designed to detect avian
leukosis viral subgroup-E, amplified a product of
approximately 265 base pairs in 8 of 13 (61.54%)
tested vaccines (Table 2 ). However the presence ALV
sub group A in the examined vaccines could be
detected in 5 samples of 13 (38.46%) using primer set
A-F and A-R (Table 2), that amplified a fragment of
246 bp. Primers J-F and J-R could amplify a fragment
of 545 bp in 2 of 13 (15.4%) examined samples .
Specificity of the RT-PCR product was confirmed
as no viral amplifications were detected in the samples
containing no RNA or DNA templates respectively