Background Brucellosis is an infectious zoonotic disease that affects humans, livestock and wildlife.

Methods A cross-sectional study was conducted in Mbeya region between November 2015 and January 2016 to investigate the seroprevalence of human brucellosis and identify associated risk factors among individuals in risky occupations in Mbeya Region. A total of 425 humans from six occupational categories were serially tested for Brucella antibodies using the Rose Bengal Plate Test (RBPT) and competitive Enzyme Linked Immunosorbent Assay (c-ELISA), for screening and confirmation, respectively. A questionnaire survey was administered to participants collect epidemiological data.

Results The overall seroprevalence among the high risk occupational individuals was 1.41% (95% CI: 0.01-0.03). Seroprevalence among the different occupations were as follows: shepherds 1.33% (95% CI: 0.14-0.22); butcher men 5.26% (95% CI: 0.10-0.17) and abattoir workers 1.08% (95% CI: 0.39-0.49). Seroprevalence was noted to vary according to occupation type, milk consumption behaviour, age and sex. Butcher men recorded the highest seroprevalence (5.0%) while individuals who consumed unboiled milk had a higher seroprevalence (1.56%) compared to those who drunk boiled milk. High seropositivity (2.25%) was observed among the age group of 1-10 years while male individuals had a higher seroprevalence (1.41%) than females (0%). Butcher men were at higher risk of exposure compared to other professions.

Conclusion Our findings show the presence of brucellosis in occupationally exposed individuals in Mbeya region. There is need to sensitize the exposed individuals in order to reduce the risk of acquiring Brucella infections from animals and animal products This also calls for public health awareness about the disease, and implementation of control measures that will prevent further spread of brucellosis within and outside the study area..

Author summary Brucellosis is a bacterial zoonosis that has evolved to establish itself as an occupational and food-borne disease Worldwide. It is responsible for huge economic losses incurred by livestock keepers and poses a public health risk to humans in most developing countries. In Tanzania, which has the 3^rd highest cattle population in Africa, many studies that have been done show that brucellosis exists in livestock, especially in cattle and wildlife. However, very few studies have reported on human brucellosis. The disease has been reported to occur in humans who have direct exposure to cattle or cattle products like livestock farmers, abattoir workers, veterinarians, shepherds and farm workers in many developing countries. A few studies in Tanzania have reported seroprevalences among these high-risk occupations; however, the disease has not been fully described in Mbeya region. This study was therefore aimed at filling these information gaps and contributing to the existing body of knowledge.