Novel in-ovo chimeric recombinant Newcastle disease vaccine protects against both Newcastle disease and infectious bursal disease.

Development of a safe and efficient in-ovo vaccine against Newcastle disease (NDV) and very virulent infectious bursal disease virus (vvIBDV) is of great importance. In this study, a chimeric NDV LaSota virus with the L gene of Clone-30 (rLaC30L) was used to generate a recombinant chimeric virus expressing the VP2 protein of vvIBDV (rLaC30L-VP2). The safety and efficacy of rLaC30L-VP2 in-ovo vaccination was then evaluated in 18-day-old special pathogen free (SPF) chicken embryos and commercial broiler embryos for prevention of NDV and vvIBDV. Hatchability and global survival rate of the hatched birds was not affected by in-ovo rLaC30L-VP2 vaccination. However, rLaC30L-VP2 in-ovo vaccination induced significant anti-IBDV and anti-NDV antibodies in SPF birds and commercial broilers, and 100% of vaccinated chickens were protected against a lethal NDV challenge. In-ovo rLaC30L-VP2 vaccination also provided resistance against vvIBDV challenge in a significant amount of animals. These results suggest that rLaC30L-VP2 is a safe and efficient bivalent live in-ovo vaccine against NDV and vvIBDV.