Author: Stuart J. Andrews, E. Jane Poole, Kristin Stuke, Jeremy Salt
About this Publication:
Background: Newcastle disease (ND) continues to be a major constraint on the extensive production of poultry in the rural communities, as well as on the more semi-intensive and intensive production carried out by smallholders in the urban and peri-urban communities, of many low- to middleincome countries (LMICs). A number of studies have demonstrated the benefits of vaccination with helping to control this disease but few have addressed the comparative efficacy of live and inactivated vaccines, especially their duration of immunity following just a single administration, under controlled conditions. Methods: Here, we report on the efficacy of two live and two inactivated commercially available ND vaccines, administered to 6-week-old specific pathogen free (SPF) chickens, by assessing the serological antibody response, and protection against mortality following virulent challenge with a recent velogenic ND virus (NDV) isolate at 24, 40 and 53 weeks after vaccination. Results: A single administration of either of the live or inactivated vaccines induced high levels of protective circulating antibody which peaked 4 weeks after vaccination and was sustained for at least 53 weeks post-vaccination. Reasonably high levels of protection against mortality, following challenge, were also demonstrated from 24 weeks up to 53 weeks after vaccination. Conclusions: These data demonstrate that in SPF chickens, kept under controlled laboratory conditions, commercially available live and inactivated ND vaccines can provide protective immunity following a single administration for at least one year. Further studies should be carried out in more intensively managed production systems using single-aged flocks to confirm our results. These studies should primarily be based on sero-monitoring. For extensively reared village and backyard chickens, which are kept in multi-aged flocks, it is strongly recommended that the current advice on the use of ND vaccines, requiring multiple vaccinations each year, is followed.
Subject Areas: Research and Development
Diseases: Newcastle Disease