Knowledge of brucellosis, health-seeking behaviour, and risk factors for Brucella infection amongst workers on cattle farms in Gauteng, South Africa

Abstract

Brucellosis in humans is under-detected and underreported in sub-Saharan Africa. Risk factors associated with Brucella infection and health seeking behaviour in response to brucellosis-like symptoms, amongst cattle farm workers and veterinary officials in South Africa, are unknown. Farm workers and veterinary officials (N = 230) were screened for brucellosis using commercial Rose Bengal Test (RBT®), IgM Enzyme-linked Immunoassay (ELISA)®, IgG ELISA® and the BrucellaCapt® test. Knowledge of brucellosis and risk factors for exposure to Brucella were also investigated. Seroprevalence varied according to test used: 10.1% (RBT®), 20.9% (IgG ELISA®) and 6.5% (BrucellaCapt®). Only 22.2% (6/27) of veterinary officials opt to visit a clinic, doctor, or hospital in response to selfexperienced brucellosis-like symptoms, compared to 74.9% (152/203) of farm workers (p < 0.001). Of the BrucellaCapt® seropositive participants, 53% (7/15) did not visit a clinic in response to brucellosislike symptoms. Weak evidence of an association between the handling of afterbirth or placenta and infection of a short evolution (RBT®, IgM ELISA® and IgG ELISA® seropositive) was found (OR = 8.9, 95% CI: 1.0–81.1, p = 0.052), and strong evidence of an association between this outcome and the slaughter of cattle (OR = 5.3, 95% CI: 1.4–19.6, p = 0.013). There was strong evidence of a positive association between inactive/resolved infection and veterinary officials vs. farm workers exposed to seropositive herds (OR = 7.0, 95% CI: 2.4–20.2, p < 0.001), with a simultaneous negative association with the handling of afterbirth or placenta (OR = 3.9, 95% CI: 1.3–11.3, p = 0.012). Findings suggest a proportion of undetected clinical cases of brucellosis amongst workers on cattle farms in Gauteng.