Background: Turkeys are susceptible to many virus diseases such as turkey rhinotracheitis (TRT) and
avian influenza (AI) that affect their populations in a dramatic form. Successful control of these viral
diseases depends on the implementation of well-designed vaccination programs using highly potent
and safe vaccines.
Aim: The present study investigated the effect of simultaneous administration of inactivated AI
vaccine and live attenuated TRT vaccine on the immune response of turkey chickens.
Methods: Four groups of bronzy turkey chickens were used in this study; group-1 received live
attenuated TRT vaccine, group-2 received inactivated AI vaccine, group-3 received TRT and AI
vaccines and group-4 served as non-vaccinated control. The humoral immune response evaluated
serologically by using hemagglutination inhibition test (HI), serum neutralization test (SNT), and
Results: There was detectable TRT antibody titers by SNT in the first week post vaccination as 4 log2
in group-1 and 2 log2 in group-3. Both groups showed peak SNT titer (256 log2) of TRT virus by the
third-week post administration of the second dose and remain stable up to 24 weeks post vaccination.
Follow up avian influenza antibody titers using HI test, peak titer (64 log2) was detected in group-2 and
group-3 by the second week after receiving the second dose then began to decrease in both groups by
third-week post the second dose to reach the zero level at week twenty-four. ELISA test confirm the
results of SNT and HI.
Conclusion: There is no antagonizing effect between the two vaccines on the immune response of
turkey chickens against each other as all vaccinated birds exhibited good levels of specific TRT and AI
antibodies. Therefore, it is possible to vaccinate turkeys simultaneously against TRT and AI safely and