Seroprevalence and Risk Factors of Bovine Brucellosis in Khartoum State, Sudan

Abstract

A cross-sectional epidemiological study was carried out between April and July 2012, to determine the prevalence and identify risk factors for seropositivity of bovine brucellosis in cattle farms in Khartoum State. The study populations comprised indigenous breed, cross and exotic breed of cattle in the region, and the samples were selected by multistage random sampling method. Three hundred serum samples from 30 cattle herds located in 5 different localities within the Khartoum state were screened for brucellosis using Rose Bengal Plate Test (RBPT). Bovine brucellosis was detected in all five localities in Khartoum state, and out of the 30 herds studied, 23 were seropositive by (RBPT). The overall brucellosis herd prevalence (HP) was (76.7%). Within herd prevalence ranged between 0% - 80%. Out of 23 positive herds, 19 herds (82.9%) had at least one positive reactor confirmed positive by c-ELISA. Out of a total of 300 serum samples tested, 77 (25.7 %) reacted positive for brucellosis using the Rose Bengal Plate Test (RBPT). Fifty one of these sera positive to RBPT were confirmed positive by c-ELISA. All positive samples to RBPT also subjected to Serum Agglutination Test IX (SAT) to read the titer of positive, 69 of these sera had titer > 53 IU/ml. Moreover, information was gathered on individual animal and farm-level risk factors and other farm characteristics using a questionnaire. The results of the univariate Chi-square analysis revealed that seropositivity to brucellosis was significantly higher in animals kept under the dairy farming system than animals in the mixed production system (P <0.25). The results also indicated that there was a statistically significant increase in seroprevalence to brucellosis in herd with history of retained placenta (P < 0.25). Significant increment of seropositivity was also observed in case of using artificial insemination (AI) compared to natural insemination (P < 0.25) and then both methods (P < 0.25). Also there was a statistically significant increase in seroprevalence to brucellosis in absence of veterinary service, and also there was a statistically significant increase in seroprevalence to brucellosis in herds that shared male for breeding. In addition, a significantly higher seroprevalence was found in animals milked by manual milking method than those milked by machine. However, in the multivariate logistic regression analysis, no risk factors were found statistically significant with brucellosis. The results of this study showed that brucellosis is an endemic and widely distributed disease in Khartoum state.