Sero-prevalence of Brucellosis and associated risk factors to Brucella pathogen in Tiaty, Baringo County, Kenya

Abstract

Brucellosis is a global zoonotic disease caused by Brucella pathogen, which affects man and animals. The disease has been reported across the world including Kenya. Information regarding the sero-prevalence and risk factors of brucellosis in camels in the pastoral Tiaty is still scanty despite several reported loss of camels due to zoonotic diseases. The main objective of this study was to investigate sero-prevalence of brucellosis, and the Risk factors associated with Brucella pathogen infections in Tiaty Sub-county, Baringo County. Thus a cross-sectional study was conducted in the study area whereby a total of 105 sera samples were collected from camels i five study locations, dominated by camel farmers using a multi stage sampling technique. The samples were tested to detect antibodies against Brucella by competitive immunosorbent assay (cELISA) as per the manufacturer’s instructions. In addition, data, on location of camels, history of retained placenta or abortion, gender, and age was gathered using a questionnaire. DNA extraction and purification was done on the positive samples using the Norgen bacterial genomic DNA isolation kit, then the quality and quantity of DNA were determined according to the manufacturer’s instructions. The data on risk factors was analyzed using chi-squared test (X2) at 95% confidence interval (CI) to investigate the relationship between brucellosis and the risk factors. The overall sero-prevalence of 20.0% was reported in camels. The percentage sero-prevalence per study location indicated that Ribikwo had the highest seroprevalence of 38.1% while Silale recorded the least 14.3%. Chemolingot, Lolyamorok and Kollowa locations recorded 28.6%, 19.0% and 0.0% respectively. The proportions of seropositivity in the study locations were significantly higher which revealed a significant association between sero-positivity of camel brucellosis with the location, (p ═ 0.037). It was revealed that brucellosis was associated with age and gender of the camels, further logistic regression analysis on gender revealed that there was 4 times more likelihood of females being seropositive as compared to males (OR = 4.329, 95% CI = 0.971-19.307, P-value 0.050). Further, logistic regression analysis on age revealed that there was 5.8 times more likelihood of seropositivity of brucellosis occurring in camels < 2 years old compared to those aged 2-3 years and those over 3 years old (OR = 5.845, 95% CI = 1.340-25.489, P-value 0.019). History of abortion was found to have no significant association with camel brucellosis which implies that abortions in camels is mainly not linked to brucellosis. Further logistic regression analysis on the age of the camels found out that there is 0.5 times more likelihood of brucellosis occurring in camels with history of abortion (OR = 0.522, 95% CI = 0.118-2.305, P-value 0.391). The high sero-prevalence reported in this study incriminates cattle, sheep and goats as the source of infection since they are reared in close association with camels. The determinant of brucellosis seropositivity were gender and age of camels. Therefore, brucellosis control programs targeting multiple species cattle, goats’ sheep, and camel should be formulated to curb spread of the disease.