Seroprevalence, Isolation, Molecular Detection and Associated Risk Factors of Brucellosis in Small Ruminants in Selected Pastoral Districts of Oromia and Somali Regional States, (Ethiopia)

Background: Brucellosis is a bacterial zoonotic disease that has important veterinary and public health consequences as well as economic impact in sub Saharan Africa, including Ethiopia. The purpose of this study was to detect Brucella DNA from isolates and blood clots, to estimate the prevalence of brucellosis and assess associated risk factors in sheep and goats.

Methods: The cross-sectional study was conducted in four selected districts of Oromia and Somali Pastoral areas, Southern, Ethiopia from April 2020 to December 2021. 14 vaginal swabs and 7 whole blood samples were purposefully collected from animals that had recently undergone an abortion. A total of 841 serum samples (267 from sheep and 574 from goats) were collected. Antibodies against Brucella infection was detected by multi-species indirect enzyme-linked immunosorbent assay, isolation of Brucella was performed by selective media, real time PCR for DNA detection, and Ct value. Using a standardized questionnaire, data from individual animals and flocks was collected to investigate the association between expounding and outcome variables. The data was evaluated using STATA version 14.0.

Results: The overall seroprevalence rate was 12.84% (108/841), 6.7% (18/267) in sheep and 15.6% (90/574) in goats. No Brucella organism was isolated from vaginal swabs and blood culture. An analysis of 108 seropositive blood clots for Brucella DNA revealed that 15/108 (13.9%) tested positive for the universal primers (IS711). For Brucella specious DNA detection, species-specific primers were employed, 13/15 (87%) positive for Brucella abortus and melitensis, while two genera were not respond. Furthermore, 95% of owners who were interviewed did not have knowledge of brucellosis. The univariable logistic analysis and a multivariable revealed statistically significant differences (p 0.05) among age groups (OR: 0.29 (95% CI: 1.8-9.94)), species (OR: 0.45, 95% CI: 0.26–0.77), and abortion history (OR: 0.05 (95% CI: 0.24-1.22)) While there was no significant difference between sexes (p-value > 0.05).

Conclusion: Brucellosis is endemic in the pastoralist area and could lead to abortion, infertility, and productivity losses. The diseases can spread from infected animals to humans and other animals. Therefore, one-health and integrated intervention strategies are needed to restrict the disease's spread, and pastoral communities should regularly raise awareness of brucellosis control methods.