Intranasal Inactivated Recombinant Mannheimia hemolytica Vaccine is not protective against naturally occurring Pneumonia in Nigerian Goats

Abstract

Pneumonia had been a major constraint to the development of small ruminant production and its control is expedient. This experiment was conducted to evaluate the protective effect of intranasal recombinant Mannheimia hemolytica vaccine against naturally occurring pneumonia in Nigerian goats. Twenty one goats were divided into five groups. Five goats each were in vaccinated groups while three goats were in the control groups. Group A was vaccinated once; group B was vaccinated twice at one week interval, and group D at two weeks interval, while group C and E were the positive and negative control groups. All goats including the vaccinated groups were challenged two weeks after the last vaccination by comingling with goats that had pneumonia for three weeks. The clinical, bacterial isolation, virus detection, lung consolidation, gross and histopathological score were employed using standard techniques. All data were analyzed statistically using the one-way analysis of variance (ANOVA). Group C and D had the highest clinical score following challenge while deaths were observed in all with the lowest in group B. The lung consolidation score and lesions in group C and D were significantly (P<0.05) severe than A and B. Similarly, the lesions in group B was lower than A (P>0.05). This study showed that the recombinant MH vaccine reduced the clinical manifestations especially when administered at a week interval more than once but was not sufficient to protect against naturally occurring caprine pneumonia commonly observed hence a need for modification to be effective in Nigeria.

Keywords: Intranasal route; pneumonia, Nigerian goats, recombinant Mannheimia hemolytica vaccine