Comparative Tissue Reactivity Of Three Lentogenic Strains Of Newcastle Disease Vaccines In Nigeria

Abstract

The comparative safety of a viscerotropic and lentogenic Newcastle disease vaccine strain, NDvac-1 (VG/GA strain) and two other proprietary lentogenic Newcastle disease vaccine strains in Nigeria, NDvac-2 (R2B) and NDvac-3 (LaSota) were studied. Safety parameters adopted in the investigation included: post vaccination clinical reactions; gross and histopathological changes in various tissues. The eyelids, sinus, trachea, lung and ceacal tonsil were examined for post vaccination reactions and observed lesions were scored on a scale of 1 - 4.Although clinical reactions and gross pathological lesions were absent following vaccination in each of the four experimental vaccination groups, there were histological reactions with total lesion scores attaining 3,5,14, 12, and 1 in the NDvac-1, double dose NDvac-1, NDvac-2, NDvac-3 and the unvaccinated control group respectively at day 3 post –vaccination. The least scores of 3 and 5 in the NDvac-1 vaccinated groups implied superior safety in association with the conventional and double dosage of the vaccine. The ND-vac-2 vaccinated group with the maximum score of 14 was found to be the histopathologically most reactive of the three vaccines.

Keywords: Comparative, Tissue reaction, Newcastle disease vaccines

Nigerian Veterinary Journal Vol. 28 (3) 2007 pp. 6-10