Bovine tuberculosis and brucellosis prevalence in cattle from selected milk cooperatives in Arsi zone, Oromia region, Ethiopia

BACKGROUND: Bovine tuberculosis (BTB) and bovine brucellosis are two important milk-borne zoonoses that have been shown to be prevalent to various degrees in Ethiopian cattle. The study was carried out in four Woredas (districts) around Asella town, Arsi Zone between October 2011 and March 2012 and included 318 small-holders in 13 dairy cooperatives that marketed the delivered milk. The aims of the study were i) to assess the prevalence of the two diseases in cattle in a cross-sectional study, ii) to assess potential risk factors of BTB and brucellosis to humans as well as the knowledge-attitude-practice (KAP) among these farmers towards these diseases. RESULTS: BTB testing using the comparative intradermal skin test (CIDT) was done on 584 milking cows, out of which 417 were serologically tested for brucellosis using the Rose Bengal Plate Test and reactors confirmed with an indirect ELISA test (PrioCHECK®). The individual animal prevalence was 0.3% (95% CI 0.1% to 1.3%) for BTB, 1.7% (95% CI 0.8% to 3.5%) for brucellosis and 8.9% (95% CI 6.8% to 11.5%) for MAC (Mycobacterium avium complex). Of the 13 milk cooperatives, two had at least one positive BTB reactor and five had animals positive for brucellosis. Cross-breeds accounted for 100% and 71.4% of the BTB and brucellosis reactors respectively. For both diseases, there were prevalence variations depending on Woreda. No animal was concomitant reactor for BTB and brucellosis. Raw milk was consumed by 55.4% of the respondents. 79.2% of the respondents reported touching the afterbirth with bare hands. The latter was fed to dogs in 83% of the households. One cow among the herds of the 130 interviewees had aborted in the last 12 months. Among the interviewees, 77% stated knowing tuberculosis in general but 42 out of the 130 respondents (32.3%) did not know that BTB was transmitted by livestock. Less than half (47.7%) of the respondents knew about brucellosis. CONCLUSIONS: Low prevalence of both diseases reflected the potential for the area to compete with the growing milk demand. The authors discussed the possible control strategies for the area.