Sero-Prevalence and Risk Factors of Small Ruminant Brucellosis in Selected Districts of West omo and Kafa Zones, south Western Ethiopia

A cross-sectional study was conducted from December 2023 to July 2024 to estimate sero-prevalence and assess the risk factors of brucellosis in small ruminants in selected districts of West Omo and Kafa zone of southwestern Ethiopia. A total of 552 (341 goats and 211 sheep) serum samples were collected from 80 flocks by simple random sampling method and two serological testing was performed using a Rose Bengal plate test (RBPT) for screening and indirect enzyme-linked immunosorbent assay (i -ELISA) for confirmation of small ruminant brucellosis antibodies. The overall sero-prevalence of brucellosis was 4.17% (95% CI 2.8 to 6.2) at individual animal level and 20% (95% CI 12.7 to 30) at herd level. Multivariable regression analysis showed that the odd of seropositivity in larger herds were 4.69 times greater than that of seropositivity in small herds. Brucellosis sero-prevalence was also significantly associated with animals that had prior history of abortion (95% CI: 1.614-14.175 OR = 4.78, P < 0.005) which had 4.78 times higher risk of developing brucellosis. Those animal with retained fetal membrane were found to be 6.83 times more likely to be at higher risk of Brucella infection compared with no history of retained fetal membrane with (95% CI: 2.178-21.472 OR = 6.83, P < 0.001). Seroprevalence of brucellosis was also significantly associated with female animals those had prior history of still birth with 6.08 times more likely susceptible for Brucella infection than those animals without prior history of still birth (95% CI: 1.846-20.039, OR = 6.08, P = 0.003). This study confirms the moderate infection of small ruminant brucellosis in the study area.

⓿ The overall sero-prevalence of brucellosis among small ruminants was within the range commonly reported in Ethiopia.

⓿ Goats showed a higher seroprevalnce than sheep, suggesting greater susceptibility.