Vaccines interaction and protection against virulent avian metapneumovirus (AMPV) challenge after combined administration of Newcastle disease and AMPV live vaccines to one-day old turkeys

The combined administration of Newcastle Disease (ND) and Avian metapneumovirus (AMPV) live vaccines to one-day-old turkeys in the hatchery is advantageous, but compatibility has not yet been experimentally demonstrated. To investigate this issue, AMPV subtype B live vaccine strain VCO3 was given to one-day old turkeys either alone or in combination with ND vaccine strain B1 or strain VG/GA, in secure isolation conditions. Post-vaccination viral shedding and humoral immune response were assessed. Furthermore birds were challenged with a virulent AMPV and the protection from clinical signs was evaluated. Results showed that concurrent live vaccination with AMPV and NDV (either strain B1 or VG/GA) of 1-day-old turkeys confers good protection after AMPV challenge and causes a synergic effect in AMPV antibody response, probably due to higher AMPV vaccine replication when it is given in combination with ND vaccines. Further studies are required to show if protection after NDV challenge is affected by ND and AMPV combined vaccination.