Seroprevalence of bovine brucellosis and associated factors among dairy cows with recent cases of abortion in Ethiopia.

Background: Brucellosis is a serious zoonotic disease affecting human and all domestic animals. It is considered to be one of the great public health problems all over the world. Little attention has been paid to bovine brucellosis in small holder dairy farm and in animal owners and farm workers in central highland of Ethiopia. This research was conducted with the aim of determining seropositivity and identifying the potential risk factors of brucellosis in dairy cows with recent cases of abortion in the central highlands of Ethiopia.

Methods: This was a cross-sectional study with purposive sampling carried out on dairy cows in the farms and kebeles from December 2019 to May 2020. The serum samples were initially screened for brucellosis using the Rose Bengal plate test (RBPT) followed by the complement fixation test (CFT) for confirmation. The risk factors for bovine brucellosis were assessed using univariable Firth bias reduced logistic regression.

Results: A total of 352 samples were tested. Serological positivity for bovine brucellosis was detected in 1.2% (95% CI: 0.47-2.97) by RBPT, and bovine brucellosis confirmed by CFT was 0.6% (95% CI: 0.16-2.09). The risk factors for confirmed bovine brucellosis were the late stage of abortion (OR = 1.046, p = < 0.0041), retained fetal membranes (OR = 32.74, p = 0.006), and market-based stock replacement (OR = 1.0638, p = 0.0008), which are significantly associated at 95% confidence interval.

Conclusion: The proportion of brucellosis among aborted cows seems to be low in the study area. However, given the lack of control strategies in the area, there is a potential risk of transmission in dairy cattle and the human population in the study areas.