Bovine tuberculosis at the human-livestock-wildlife interface and its control through one health approach in the Ethiopian Somali Pastoralists: A review

Abstract

Pastoralism is a way of life in which food supply is produced from animals by using a variety of herding practices based on constant or partial herd mobility in the low land areas of Ethiopia. It covers 12% of the total livestock population and 61% of the total area of land in the country. As a result of their mobile lifestyle, pastoralists are almost completely excluded from the available health services. This review article focuses on bovine tuberculosis in the Ethiopian Somali Pastoralist. It describes Mycobacterium bovis in humans, livestock, and wildlife, and how the disease can be controlled by using One Health approach. Bovine tuberculosis is a chronic bacterial disease caused by Mycobacterium bovis. A study done from 2006 to 2008 on the prevalence of BTB in Ethiopian wildlife showed that sera from 20 of 87 animals (23%) were positive for BTB. In Ethiopia there is no comprehensive report about the status of M. bovis in wildlife populations that often share habitat with livestock. A study done on bovine tuberculosis in Somali pastoral livestock showed low prevalence of the disease. An individual animal prevalence of 2.0%, 0.4%, and 0.2% was reported in cattle, camels, and goats, respectively. In a simultaneous human and cattle study in a pastoralist areas of south-eastern Ethiopia, out of 163 human Mycobacterium tuberculosis complex isolates three were M. bovis. Due to the moderate resistance of the etiological agent to the environmental conditions in one hand and the capacity of its survival in acid milk for not less than 15 days on the other and the habitual consumption of unpasteurized milk by humans make this disease a vital zoonosis in Somali pastoralists in Ethiopia. M. bovis is a pathogen at the human-livestock-wildlife interface. Diseases transmitted between humans, livestock, and wildlife are increasingly challenging public and veterinary health systems. Therefore, studies concerning the burden of the diseases in wildlife, livestock and human beings in Somali Pastoralists should be undertaken. A One Health approach that takes the wellbeing of the pastoralists, the health of their livestock and environment into consideration is also necessary for the control of BTB.

Keywords: Bovine TB; Livestock; Mycobacterium bovis; One health; Somali pastoralists; Wildlife.

Fig. 1

Interspecific transmission of bovine tuberculosis (bTB) at wildlife–livestock–human interfaces in Africa. Bovine TB can be maintained in livestock (bTB in livestock) and in wildlife (bTB in wildlife), promoted by factors indicated in italics with a grey arrow (e.g. diversity of wildlife, production system). Risks of bTB spillover from livestock to wildlife or humans, and spillback from wildlife to livestock, are indicated in boxes with black arrows (e.g. environmental conditions, human behavior, etc.) .