Protection of bivalent HVT and IBDV-immune complex vaccine against very virulent Marek’s disease virus (RB1B) challenge after in ovo vaccination of SPF eggs
Dren C. et al., 2005. World Veterinary Poultry Association Congress.
18-day old embryonated SPF eggs.
· Cell-associated HVT, in ovo: 58 eggs;
· Cell-associated HVT in mixture with Cevac® Transmune, in ovo: 54 eggs;
· Unvaccinated controls: 46 eggs.
6 days after hatch, all chicks were challenged using 100 PFU of the very virulent RB1B strain of Marek’s disease virus, by intramuscular route. Birds were observed for the onset of clinical signs and gross lesions for 72 days.
A relative protection index was calculated:
· HVT alone: 42%
· HVT + Cevac Transmune: 70.5%.
These results demonstrated the compatibility of Cevac® Transmune with HVT frozen vaccine in terms of Marek protection.