Dr. Moses Kyule, Dr. Kelay BelihuDr. Shewit KalayouMEKONNEN, HAILESELASSIE2020-06-172023-11-082020-06-172023-11-082008-06http://etd.aau.edu.et/handle/123456789/21676A cross sectional study was conducted to determine the seroprevalence and associations with potential risk factors of brucellosis in cattle and humans in western zone of Tigray Regional State between October 2007 and February 2008. A two-stage cluster sampling method was used in this study. A total of 1968 cattle were examined. Of these 1120 cattle were examined from semi-intensive production system and 848 cattle from extensive one. Human risk groups to brucellosis were purposively sampled. Sera sampling was carried out from all cattle above six months of age with no history of previous vaccination against brucellosis. The types of tests used to detect the presence of Brucella antibodies were Rose Bengal Plate Test and Complement Fixation Test. The overall individual animal prevalence was 4.9%. There were high significant differences (P=0.000) in seroprevalence to Brucella antibody between semi-intensive and extensive production systems. The seroprevalence to Brucella antibodies among nine towns in the semi-intensive and the three districts (Hmera, Tsegede and Welkait) at both individual and herd levels in the extensive production system were comparable. Seroreactor in both sexes of cattle were varied significantly. Females were more infected. Seroprevalence by categories of ages and herd sizes were significantly different. Higher risk to infection was found in Barka breeds than Arado in the semi-intensive production system but not in the extensive production system. History of abortion was found significantly (P=0.001) associated with brucellosis. Watering points and culling methods of management and husbandry related factors were significantly associated with seropositivity to brucellosis and brucellosis increased the calving intervals. In a total of 246 vulnerable groups of humans to brucellosis 1.2% overall seropositive to Brucella antibodies were obtained with all positive reactors being herdsmen. There was a high risk of acquiring the infection during removal of retained fetal membranes and in those who were both in contacts with animals and drank raw milk. A high prevalence of brucellosis in Barka breeds in the study area indicates that it might serve as source of infection for others in the region. Hence, before distributing this breed screening test for brucellosis is recommended. While in case of human brucellosis, since its presence is confirmed and the risk factors were identified, the medical personnel should give attention to its differential diagnosis with aims of offering specific therapies to true cases and creating awareness via education campaigns to human risk groups.enBreedCattleCross-sectional surveyBrucellosisHumanProduction systemThesis