Effects of Live Infectious Bursal Disease Vaccines, on Immune Response of Vaccinated Chicks
Maduike C. O. Ezeibe *
Department of Veterinary Medicine, University of Nigeria, Nsukka, Nigeria.
John O. A. Okoye
Department of Veterinary Microbiology and Pathology, University of Nigeria, Nsukka, Nigeria.
Temitope M. Ogunniran
Department of Veterinary Medicine, University of Nigeria, Nsukka, Nigeria.
Paul C. Animoke
Department of Veterinary Medicine, University of Nigeria, Nsukka, Nigeria.
Ijeoma J. Mbuko
Department of Veterinary Medicine, University of Nigeria, Nsukka, Nigeria.
Ijeoma A. Nwankwo
Department of Veterinary Medicine, University of Nigeria, Nsukka, Nigeria.
Augustine A. Ngene
Department of Veterinary Medicine, University of Nigeria, Nsukka, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Aim: Relationship between virus titers of live Infectious Bursal disease (IBD) vaccines and their serum-conversion abilities was studied.
Study design and Methodology: Five batches of each, of five IBD vaccine brands used in Nigeria, were tested for virus titers. Each of the vaccine brands was also used to vaccinate a group of fifteen 12-days old chicks to study their serum-conversion abilities. Mean antibody titers of the groups of chicks were plotted, on a graph, against virus titers of the vaccine brands used to vaccinate them.
Results: Mean Modified Passive Haemagglutination titers of IBD virus in the vaccines,were:1,065.60±780.03,1,472.00±748.55,2,112.00±1984.00,2,176.00±1920. 00 and 2,585.00±926.92 while mean antibody titers they elicited were, 1,356.80±241.51, 1,280.00±174.88, 448.00±79.25, 998.40±196.27 and 332.80±51.20, respectively. Line of best fit of graph of antibody titers of vaccinated chicks on vaccine titers, showed that reducing titers of the live IBD vaccines improved their immunogenicity.
Conclusions: The inverse relationship between virus titers of the vaccines and their serum conversion abilities, suggests that, if viral titers of live IBD vaccines are too high, immune-suppression instead of enhancement of immune response may occur.
Keywords: Live vaccines, Immune-suppression, Infectious Bursal Disease Virus.