Effects of peste des petit ruminants N/75/1 vaccine on nasal bacterial flora and clinical indices in Red Sokoto goats

Abstract

Peste des petit ruminants virus (PPRv) and Mannheimia haemolytica have been commonly implicated in naturally occurring pneumonia in sub-Saharan Africa and account for huge economic losses as they are associated with high morbidity and mortality. The Nigerian 75/1 PPR vaccine has been proven to be efficacious in the control of PPR. However, there is a paucity of information on the ability of this live attenuated vaccine to modulate bacteria of the nasal flora to control or confer protection against secondary bacterial infection induced especially by M. haemolytica. Nasal swabs and blood samples were collected for bacterial count and serology respectively. This study describes the effect of the N/75/1 PPR vaccine on the nasal bacteria flora and clinical indices of Red Sokoto goats. Ten (10) Red Sokoto goats were divided into two groups of five animals each. In one group, 1ml of PPR vaccine (2.5 TCID50) was administered subcutaneously while the other group served as control and 1ml of normal saline was administered subcutaneously. The results showed that for the PPR vaccinated group, although there was a significant decrease (p≤0.05) in nasal bacteria counts for Mannheimia haemolytica, Pasteurella multocida and Escherichia coli compared to the control group it was not sufficient to clear out these potentially pathogenic bacteria from the nasal flora. Also, in the PPR-vaccinated group, the only clinical symptom observed was a mild transient and self-limiting hyperthermia at about 2 weeks post-vaccination which may be attributed to the initiation and enhancement of immune responses. Hence, it can be deduced that the PPR vaccine may moderately inhibit the colonization of certain pathogenic bacteria of the nasal microbial flora but however, it is incapable of conferring total immunity against the secondary bacterial infection in naturally occurring pneumonia.