Prevalence and factors associated with brucellosis in humans and animals in Kajiado county, Kenya

Abstract

Introduction: Brucellosis is one of the world’s most widespread zoonosis. It is caused by gram-negative bacilli of the genus Brucella. A strategy for brucellosis control would greatly benefit from detailed knowledge of local epidemiology. The available data on brucellosis is not adequate enough to inform an effective control process. Previous studies on Brucellosis have focused either on human or animal disease. The current study simultaneously investigated the linkage in sero-prevalence between humans and their animals within the same household at the same time. . Objectives: To establish and determine the prevalence of brucellosis and identify factors associated with Brucella spp infection in humans and their livestock in Kajiado County of Kenya. Methods: A cross-sectional study involving a multi-stage sampling was carried out. Serum specimens were collected from humans and animals in enrolled households. Data collection was done using a standardized questionnaire while sera were tested using ELISA. Results: Sera from 13.9% (108/775) of individuals tested positive on indirect ELISA while 25.4% (78/307) of the households had at least one person testing positive for Brucellosis. The corresponding overall herd sero-prevalence was 29.6% (64/216). The sero- prevalence in livestock was 3.3%, 3.6% and 3.4% for cows, goats and sheep respectively. Having a seropositive animal in the herd was a predictor for human sero-positivity to Brucellosis (OR=2.0; 95%CI: 1.1-3.7) while having a seropositive goat in the herd indicated a 2.5 times chance of having a human seropositive case in the same household (OR=2.5; 95%CI: 1.1-5.7). Explanatory variables that remained significant were gender/males (OR=2.4; 95% CI:1.5-4.2), handling hides and skins (OR=1.9; 95%CI:1.2-3.1) , level of education (OR=6.4; 95%CI:3.7-11.2) and using un-boiled milk from a cow (OR=2; 95%CI:1.2-3.3) Conclusion: This study illustrates high exposure to Brucella organisms in humans within Kajiado County. Risk reduction can be achieved by consuming pasteurized milk and using protective clothing when handling or working with hides and skins. Livestock keepers should be informed of the dangers of using un-boiled milk, especially from herds other than their own. The role of goats in the transmission of the disease to humans should be explored by way of culture and typing.