Bovine brucellosis and tuberculosis at a livestock–wildlife interface in Zimbabwe: A nexus for amplification of a zoonosis or a myth?

Background Bovine brucellosis and tuberculosis are important zoonoses affecting both livestock and wildlife. Objectives The study aimed to investigate seroprevalence of brucellosis and to isolate Brucella spp. and Mycobacterium bovis in cattle from livestock–wildlife interface areas. Methods Three sites were selected from high, medium and low interface. The high interface was adjacent to the park and separated by a broken fence, while the medium and low interface were 15–20 and 50 km from the perimeter fence, respectively. Cattle aged ≥2 years were randomly selected and bled for serology. Culture for brucellae and Mycobacterium species was attempted on lymph nodes collected at the slaughter floor. Sera were screened for Brucella antibodies using the Rose Bengal test and confirmed by the Complement fixation test. Data were analysed using a multivariable logistic regression model. Results Overall, seroprevalence was 11.7% (125/1068; 95% CI: 9.8–13.6%). High interface areas recorded significantly higher (p < 0.05) seroprevalence of 20.9% (85/406; 95% CI: 17.0–24.9%), compared to low 8.9% (31/350; 95% CI: 5.9–11.8%) and medium interface 2.9% (9/312; 95% CI: 1.0–4.8%). Brucella seropositivity was approximately three times higher (OR = 3.3, 95% CI: 2.1–5.3) for Malipati compared to Chiredzi. Similarly, the odds were twice (OR = 2.0, 95% CI: 1.2–3.5) in cows with history of abortion compared to those without. Brucella and Mycobacterium species were not isolated from all samples. Conclusions The study highlighted the significance of high interface as a nexus for amplification of brucellosis in cattle. Thus, a brucellosis control programme that takes into consideration limiting livestock–wildlife interaction should be considered. The high‐interface area of Malipati, on the periphery of the Gonarezhou National Park in the southeast lowveld of Zimbabwe, is separated from the park by a broken fence, allowing unlimited interface between livestock and wildlife. The study shows increased odds of Brucella seropositivity in cattle in these areas. Thus, the high interface provides a nexus for amplification of brucellosis in cattle, highlighting the public health importance of the disease to the communities living at the periphery of the park.