Seroprevalence of bovine brucellosis and associated risk factors among cattle in Bubeke Sub county, Kalangala District
Abstract
Brucellosis, a zoonotic disease caused by bacteria of the genus Brucella, poses a significant threat to both animal and human health. Several species of Brucella exist and these affect different animal species including Brucella abortus affecting mainly cattle, Brucella melitensis affecting mainly small ruminants, Brucella suis affecting swine or pigs mainly and Brucella canis affecting mainly dogs and so on. Brucella species are facultative intracellular pathogens that can survive, multiply, and persist within phagocytic cells of the host resulting in lifetime carriage of the organism. Diseased animals shed the pathogen in uterine discharge, vaginal discharge, and milk, and these bacteria can spread within the herd through ingestion of contaminated feed and water, sexual contact, or direct contact with infected placental or uterine discharges. Understanding the sero-prevalence of brucellosis and its associated risk factors is crucial for effective disease management and public health interventions. This study aimed to determine the seroprevalence of brucellosis and associated risk factors among cattle in Bubeke Sub County, Kalangala District. In this cross-sectional study, a total of 389 heads of cattle were sampled across eight farms, which were purposively selected in the study area. The number of animals per farm was determined using a proportionate sampling method.Blood sample from each animal together with animal related data including age, sex, breed, abortion history and vaccination history were collected. A close ended questionnaire was administered to each respondent to gather information on risk factors associated with brucellosis sero-prevalence. The questionnaire covered respondent socio-demographic factors such as age, gender, marital status, level of education, and farming experience. The collected blood samples with formed serum were taken to the diagnostic pathology laboratory at the college of veterinary medicine animal resources and biosecurity, where serum was aliquoted and seroprevalence tests involving Rose Bengal
Plate test procedures were carried out. Laboratory results revealed that out of the 389 sampled animals, 114 animals tested positive
for brucella antibodies in serum, and the remainder, 275 animals, tested negative. This therefore produced an overall seroprevalence of 29.3% in the sampled population in Bubeke Sub County. The risk factor assessment was done using logistic regression model in the statistical package for social sciences version 22. After running a binary logistic regression analysis, results indicated that among the management related factors, failure to isolate animals that abort, improper disposal of afterbirth and living with a dog on farm were the only significantly
associated factors with seroprevalence. However after running the multivariate logistic
regression analysis, results showed that none of the factors, including animal and management
related, were significantly associated with seroprevalence. Hence factors such as age, sex,
breed, abortion history, grazing method, interaction with other animals, isolate aborted, proper afterbirth disposal, live with a dog and consumption of raw milk were generally found to be statistically non-significant contributors to brucellosis sero-prevalence. These were not the
primary drivers in this specific context, however with their role not being undermined. In conclusion, the sero-prevalence rate among the sampled cattle was found to be 29.3%, which
scored the endemic nature of brucellosis within Bubeke Sub County. This high prevalence signifies the urgent need for comprehensive strategies to mitigate the impact of the disease on both animal health and public health. The study demonstrated that, failure to isolate aborting animals from the herd, failure to properly dispose off the after birth and dog-cattle interaction were the only statistically significant risk factor associated with brucellosis seroprevalence upon binary logistic analysis. These findings emphasize the intricate interplay among animal behaviors, management practices, and disease transmission. The lack of statistical significance in several risk factors prompts further investigation into the nuanced dynamics of brucellosis transmission. Factors like age, sex, breed, and history of abortion might still play secondary roles in certain scenarios or in combination with other factors. Additionally, the influence of factors such as grazing methods, interaction with other animals, and consumption of raw milk may vary based on local practices, which warrant more in-depth exploration. Furthermore, the findings of this study emphasize the interconnectedness of animal health, human behavior, and the environment in the context of disease transmission. Zoonotic diseases like brucellosis highlight the need for a holistic One Health approach, which recognizes that the health of humans, animals, and the environment are interconnected and should be managed in an integrated manner.