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Comparison of live Newcastle disease vaccines in a simple vaccination and challenge experiment
Insights
Commercial Newcastle disease (ND) vaccines provided good protection, outperforming their allantoic fluid preparations. This study highlights the efficacy of live ND vaccines and suggests additional protective mechanisms beyond haemagglutination inhibiting antibodies.
Area of Science:
- Veterinary Virology
- Immunology
Background:
- Newcastle disease (ND) poses a significant threat to poultry worldwide.
- Live Newcastle disease virus (NDV) vaccines are crucial for controlling the disease.
- The efficacy of commercial ND vaccines and their allantoic preparations requires ongoing evaluation.
Purpose of the Study:
- To compare the protective efficacy of three live Newcastle disease (ND) commercial vaccines against their respective allantoic preparations.
- To assess the correlation between haemagglutination inhibiting antibody (HIA) response and protection against virulent NDV challenge.
- To investigate potential mechanisms of protection beyond HIA antibodies.
Main Methods:
- Day-old chicks with pre-existing HIA were spray-vaccinated with commercial ND vaccines or their allantoic preparations.
- Haemagglutination inhibiting antibody (HIA) response was measured after three weeks.
- Chicks were challenged with a pathogenic strain of Newcastle disease virus (NDV) to assess protection levels.
Main Results:
- All commercial ND vaccines conferred good and comparable protection.
- Significant differences in protection were observed among the allantoic fluid preparations.
- Two commercial vaccines demonstrated superior protection compared to their allantoic fluid counterparts.
- Protection levels varied, indicating roles for mechanisms beyond HIA antibodies.
Conclusions:
- Live Newcastle disease (ND) commercial vaccines offer robust protection.
- Allantoic preparations of ND vaccines may vary in efficacy.
- Mechanisms of protection against Newcastle disease are multifaceted, involving factors beyond HIA antibody titers.
Abstract:
Groups of day-old chicks with haemagglutination inhibiting antibodies (HIA) were exposed by the spray method to equal doses of three different live Newcastle disease (ND) commercial vaccines and allantoic preparations of them. After three weeks the HIA response was measured and the chicks were challenged with a pathogenic strain of Newcastle disease virus (NDV). The degree of protection of each bird was compared with its HIA response. The commercial vaccines all provided good protection at identical levels, but significant differences were detected between the allantoic fluid preparations. Two of the commercial vaccines produced significantly better protection than the allantoic fluid preparations. In addition to the protection conferred by HIA antibody, other mechanisms of protection apparently played a part.