Evaluation of post-vaccination flock immunity against Peste des Petits Ruminants (PPR) in small ruminants across selected districts of Borana zone, Southern Ethiopia

BACKGROUND: Peste des Petits Ruminants (PPR) is a highly contagious transboundary viral disease affecting small ruminants, with significant socio-economic consequences in areas such as Borana Zone, Southern Ethiopia. This sero-monitoring study was conducted in Yabello, Taltale, and Elwaya districts of Borana zone to evaluate the Post-vaccination immunity status of local sheep and goats against PPR. METHODS: Three stage sampling methods were used to select peasant associations (PA), villages and individual animals. A total of 901 sera samples were collected from 578 to 323 vaccinated goats and sheep, respectively. Competitive ELISA was employed as a tool of diagnosis. RESULTS: An overall sero-conversion rate of 93.23% (95% CI: 91.40%-94.69%) was recorded. Statistically significant differences in sero-conversion were observed across age groups (higher in small ruminants > 2 years; P = 0.001; odds ratio = 3.35) and history of movement (higher in those having no history of migration; P = 0.04; odds ratio = 2.15). However, no significant differences were observed among species (P = 0.95; odds ratio = 1.02), sex groups (P = 0.16; odds ratio = 2), districts (P = 0.23; odds ratio = 1.66), and timing between vaccination and sampling for sero-monitoring (P = 0.06; odds ratio = 2.18). CONCLUSIONS: The findings suggest the effectiveness of the vaccination program. The development of protective immunity in substantial proportion of goats and sheep after vaccination confirmed successful induction of flock immunity. Developing a strategy to track and manage the movement of small ruminants to minimize the introduction of unvaccinated animal is suggested.