Infectious bursal disease (IBD), Newcastle disease (ND) and Marek’s disease (MD) are key diseases of commercial poultry that are currently controlled with vaccination. This control routinely includes the use of HVT-vectored vaccines, expressing either the ND virus or the IBD virus antigens.

The single vHVT310-IBDV-NDV construct based on a vHVT013 (VAXXITEK HVT+IBD) backbone with one additional insert expressing a modified fusion (F) gene from velogenic genotype VII.2 NDV was the tested vaccine.

This vHVT310-IBDV-NDV (VAXXITEK HVT+IBD+ND) vaccine was more particularly checked in the context of control and prevention of velogenic ND, a worldwide concern. Velogenic ND is highly prevalent and deserves special attention in terms of vaccination, with the concomitant use of a live vaccine, such as the VG/GA Avinew. It can be sprayed at day-old, and then possibly administered around 10 days of age.

Main selected parameter of monitoring of vaccine take was serology using HI, anti-fusion and anti-nucleoprotein ELISAs. Challenges models of velogenic Newcastle disease were respectively based on the use of four different strains of velogenic ND virus, Herts 33 (related to genotype IV, possibly new genotype), Malaysia (related to genotypes VII), Chimulhuacan & Honduras (related to genotypes V). Mortality, clinical signs associated with Newcastle disease, shedding of challenge virus by oral and cloacal routes were monitored at D28 of age.

The HVT-vectored vaccine, alone or alongside, with one or two VG/GA Avinew sprays, displayed significant differences with unvaccinated challenged positive controls in terms of mortality, clinical signs and ND challenge virus shedding, oral and cloacal.