Mamo, Gezahegne (Professor)Tekle, Muluken2018-06-292023-11-082018-06-292023-11-082016-06http://etd.aau.edu.et/handle/123456789/4993Brucellosis is one of the most frequent contagious neglected bacterial diseases with a serious veterinary and public health importance through out the world. A cross-sectional study was conducted from October 2015 to April 2016, to determine the seroprevalence of brucellosis and isolate Brucella from small ruminants (sheep and goats) that had history of recent abortion in selected kebeles of Amibara District, Afar Region. Ethiopia. Blood samples were collected from a total of 226 small ruminants that had recent history of abortion for serological test. Subsequently, 65 specimens (28milk, 28 vaginal swabs, 2 fatal abomasal contents and 7 fetal membranes) were investigated from seropositive animals for Brucella species isolation. All serum samples collected were screened serologically using the modified Rose Bengal Plate Test (mRBPT) and sera positive with mRBPT were confirmed with Complement Fixation Test (CFT). An overall seroprevalence among small ruminants estimated at 7.52% (17/226; 95% CI: 7.41–1.36) were positive by combined mRBPT and CFT analysis, while 12.4% (28/226; 95% CI: 1.22–16.44) were found positive by mRBPT alone. Reproductive characteristics such as the stage of abortion (χ2=11.26; P < 0.001) and history of retained fetal membrane (χ2=16.53; P<0.05) were significantly associated with increased seropositivity result. A multivariable logistic regression analysis revealed that age (OR=14.57, 95% CI: 1.72–123.6), parity status (OR=8.08, 95% CI: 1.11–58.57) and stage of abortion (OR=8.94, 95% CI: 1.86–42.90) were significantly associated with Brucella infection in clinically aborted small ruminants (P < 0.05). Brucella was isolated from 9 (13.8%) samples out of the 65 bacteriological samples cultured on Brucella Selective Agar. Among the overall isolates, 3(10.7%) and 6 (21.4%) were from milk and vaginal swabs, respectively. In this study all the isolates were obtained from seropositive goats milk and vaginal swab. The isolates were B. melitensis based on biochemical test result, though further test is required to biovariant level. In conclusion, the present serological test revealed that brucellosis is moderatly prevalent among aborted small ruminants in the study area. The isolation of B. melitensis from an aborted goats milk and vaginal swabs was not substantially reported in Ethiopia until now, this report may be considered one of the indicative studies. Therefore, further extensive molecular studies of the isolates and appropriate control strategies are required to reduce its economic impact and risk of zoonotic infection in the area. Key words: Abortion, Afar Region, B. melitensis, Brucellosis, isolation, seroprevalence, small ruminantsenAbortionAfar RegionB melitensisBrucellosisisolationseroprevalencesmallruminantsThesis