Sero-prevalence and Associated Risk Factors of Brucellosis and Q-fever in Livestock and Humans in Kajiado County, Kenya

Abstract

Animal and human health is inextricably linked. People depend on animals for nutrition, socio-economic development and companionship. A cross-sectional serological study was carried out to determine the sero-prevalence of two related zoonotic diseases namely brucellosis and Q-fever in cattle, sheep, goats and humans in three sub-counties of Kajiado County. Animal serum samples were collected for three months (July to September 2012) from different farms and watering points by systematically sampling a healthy adult animal in each herd. Human blood samples were collected at the health facilities serving the study areas from patients presenting with flu-like symptoms. A total of, 250 (cattle), 167 (sheep), (167) goats and 317 (humans) samples were collected. A total of 400 samples were subjected to cELISA (COMPELISA, VLA, UK) test. 382 livestock samples from the 400 cELISA test samples were subjected to Q-fever Indirect Multispecies (cattle, sheep and goats) and 90 human samples to Coxiella burnetii ELISA IgG test. In addition, information regarding risk factors for the two zoonoses in both livestock and humans was collected using questionnaires. Risk factors were management (grazing, watering and breeding system) introduction of new stock, level of awareness of the livestock owners regarding the zoonoses and frequency of contact with veterinary extension staff; contact with contaminated environment, consumption of raw/unprocessed/under processed livestock products, close association with livestock and awareness of the diseases for human. The harvested serum samples were tested for the presence of antibodies to the Brucella organisms using the Competitive Enzyme Linked Immunosorbent Assay (Com- ELISA) and C burnetii ELISA IgG. Results indicated a low prevalence of brucellosis in humans 1.3 %but a higher prevalence of Q-fever 26%. The overall prevalence in livestock was 12.91 % and 79.3 % for brucellosis and xiii Q-fever respectively. The prevalence estimates in cattle, sheep and goats were 21.92%, 8.6 % and 7.3% for brucellosis respectively and 89.7% , 57.5% and 83.1 % for Q-fever respectively, indicating a high risk of transmission of the diseases to humans through contact or consumption of livestock products such as milk. A univariate analysis of risk factors showed that using a communal bull and introduction of new animals especially bulls were important risk factors. However other factors that were found to be significantly (p < 0.05) associated with testing positive to the disease in humans were occupation (p<0.05), method of processing meat (p<0.01), whether they process blood before taking (p<0.001), contact with aborted foetuses (p<0.029), and method of disposal of aborted foetuses and placentas (p<0.028), while communal grazing system(p<0.005) and introduction of new animals was not significant (p<0.07). The study and the data obtained strongly suggest that the two zoonotic diseases may be enzootic in the study area in human, cattle, sheep and goats and presents a serious public health problem among the inhabitants of the county and that there is need to create awareness among all concerned on the likely high prevalence of the two diseases to avoid misdiagnosis and suffering of patients. It is recommended that the veterinary personnel in Kajiado County make an effort to investigate all cases of abortions and the possible causes retained placentas that are included in their disease surveillance reports. This calls for strengthening laboratory diagnostic capacity in the county by training more veterinary and health staff and providing diagnostic equipment and reagents. Creating awareness on the causes, modes of transmission and risk factors to the zoonoses should be undertaken as soon as possible.