Seroprevalence of brucellosis in cattle and selected wildlife species at selected livestock/wildlife interface areas of the Gonarezhou National Park, Zimbabwe

Abstract

A study was conducted to investigate seroprevalence and risk factors for Brucella species infection in cattle and some wildlife species in communities living at the periphery of the Great Limpopo Transfrontier Conservation Area in south eastern Zimbabwe. Three study sites were selected based on the type of livestock-wildlife interface: porous livestock-wildlife interface (unrestricted); non-porous livestock-wildlife interface (restricted by fencing); and livestock-wildlife non-interface (totally absent or control). Sera were collected from cattle aged≥2years representing both female and intact male animals. Sera were also collected from selected wild ungulates from Mabalauta (porous interface) and Chipinda (non-interface) areas of the Gonarezhou National Park. Samples were screened for Brucellaantibodies using the Rose Bengal plate test and confirmed by the complement fixation test. Data were analysed by descriptive statistics and multivariate logistic regression modelling. In cattle, brucellosis seroprevalence from all areas was 16.7% (169/1011; 95% CI: 14.5-19.2%). The porous interface recorded a significantly (p=0.03) higher seroprevalence (19.5%; 95% CI: 16.1-23.4%) compared to the non-interface area (13.0%; 95% CI: 9.2-19.9%).The odds of Brucellaseropositivity increased progressively with parity of animals and were also three times higher (OR=3.0, 2.0<OR<4.6, p<0.0001) in cows with history of abortion compared to those without.Brucella antibodies were detected in buffaloes; 20.7% (95% CI: 13.9-29.7%) form both study sites, but no antibodies were detected from impalas and kudus. These results highlight the importance of porous interface in the interspecies transmission of Brucella species and that independent infections may be maintained in buffalo populations. Thus, brucellosis control aimed at limiting animal inter-species mixing may help reduce the risk of human brucellosis in interface areas. Further studies should aim at establishing subspecies identity and direction of possible transmission of brucellosis between wildlife and livestock.

Keywords: Brucellosis; Interface; Livestock; Wildlife; Zoonosis.