Seroprevalence and Associated Risk Factors of Human Brucellosis in a Farming and Animal Health Community in South Africa, 2015–2016

Brucellosis is a widespread zoonotic disease and a major contributor to febrile illness, often underdiagnosed. This study investigated the seroprevalence of brucellosis and the associated exposure factors within South African farming and animal health communities. A cross-sectional survey was conducted across 40,000 km² in the Free State and Northern Cape provinces from 2015 to 2016. Interviews and serum samples were collected from 847 volunteers on randomly selected farms and veterinary professionals listed in a regional register. Samples were tested using a commercial <i>Brucella</i> IgG ELISA. Risk factors were assessed using logistic regression, accounting for within-farm clustering. The seroprevalence was higher among veterinary professionals (11.6%; 16/138) than farm-based participants (7.0%; 50/711); <i>p</i> = 0.095. Multivariable analysis identified several exposure factors within the farm-based population: age over 40 years (aOR = 5.35; 95% CI: 1.68-17.02), White population group (aOR = 4.60; 95% CI: 1.64-12.91), contact with diseased animals (aOR = 2.01; 95% CI: 1.05-3.84), and working 4-8 h daily with ungulates (aOR = 2.90; 95% CI: 1.25-6.76). Among veterinary professionals, odds of exposure were higher with more than 5 years of work (OR = 1.82; 95% CI: 1.21-2.72) and extended ungulate contact (OR = 4.85; 95% CI: 1.27-18.52). Occupational exposure highlights the need for improved brucellosis prevention strategies.