Preparation Of Inactivated Infectious Bursal Disease Virus Vaccine From Classical Strain And Local Variant Isolates

This study was conducted to assess an inactivated vaccine prepared from local field isolates of Infectious Bursal Disease (IBD) "local variant and virulent isolates" and a classical strain "bursa vacc" to improve the full control over the problem of IBD in Egypt. This experiment applied on 21 day old SPF chicks divided into six groups, the first group was vaccinated with inactivated vaccine containing (local variant isolate, classical bursa vacc strain and virulent isolate), the second group was vaccinated with inactivated vaccine containing (classical bursa vacc strain and local variant isolate), the third group was vaccinated with classical bursa vacc vaccine, and the group 4 vaccinated with local variant isolate vaccine while last two groups were left as a positive and negative control groups. The immune response of chicks was evaluated in vitro by measuring serum neutralization test (SNT) and enzyme linked immunosorbent assay (ELISA) and in vivo by challenging birds with 103.5 EID50/ dose of virulent virus of infectious bursal disease virus (vvIBDV).The highest average antibody level was obtained at the 4th week post vaccination in chicks in group 1 vaccinated with (local variant isolate, classical bursa vacc and local virulent isolate) vaccine, while the chicks in group 3 vaccinated with bursa vacc vaccine showed the lowest antibody level at the same week post vaccination using SNT and ELISA. The challenge of group 1, 2, 3 and 4 showed protection of 97.5%, 90%, 75% and 90% respectively using very virulent IBDV 28 day post vaccination with no clinical signs or lesions on examination. It was concluded that we can use an inactivated vaccine prepared from (classical strain "bursa vacc" and local variant and virulent isolates) of Infectious Bursal Disease (IBD) virus as a method for control IBD disease in Egypt.