Introduction

Bovine tuberculosis (BTB) is a zoonotic bacterial disease caused by Mycobacterium bovis, a member of Mycobacterium tuberculosis complex (MTC). The members of the M. tuberculosis complex that consists of M.

The introduction of M. bovis into Africa is linked to the historical livestock trade between the UK and African countries during colonization in the nineteenth and twentieth centuries. For this reason, a number of members of the European 1 (Eu1) M. bovis clonal complex present in the UK and Ireland occur in some of the former colonies such as Tanzania, South Africa, and Zambia (Smith et al. 2011). In Africa, M. bovis, a known multi-host pathogen, became embedded in a multi-species system following spillover of the disease to various African wildlife species, some of which then became maintenance hosts (Renwick et al. 2007).

In Tanzania, M. bovis was first isolated from cattle in 1952 (Markham 1952). Currently, the infection is prevalent in all the regions of the country (Cleaveland et al. 2005; Dumez et al. 2009; Katale et al. 2013; Kazwala 1996; Mwakapuja et al.

B. Z. Katale

Tanzania Wildlife Research Institute (TAWIRI), Arusha, Tanzania

H. E. Nonga ∙ R. R. Kazwala (*)

Department of Veterinary Medicine and Public Health, Sokoine University of Agriculture (SUA), Morogoro, Tanzania

© Springer Nature Switzerland AG 2019 415

A.

2013a, b; Shirima et al. 2003). It has been detected in indigenous cattle (Kazwala et al. 1998; Cleaveland et al. 2007; Mdegela et al. 2004-; Dumez et al. 2009; Makondo 2013; Mwakapujaetal. 2013a, b; Katale et al. 2015), humans (Kazwalaetal. 2006; Mfinanga et al. 2004), and a number of wildlife species (Cleaveland et al. 2005; Katale et al.

2015) including lions (Panthera leo), blue wildebeest (Connochaetes taurinus), topi (Damaliscus lunatus) (Cleaveland et al. 2005), African buffaloes (Syncerus caffer), and the African civet (Civettictis civetta) (Katale et al. 2015). Spillover and spillback of M. bovis infection between wildlife and livestock are facilitated by anthropogenic factors such as encroachment on wildlife habitat and animal translocation (Palmer et al. 2012). Although spillover and spillback infections in wildlife, livestock, and humans are generally considered to be relatively rare in Africa (de Garine-Wichatitsky et al. 2013), the presence of maintenance hosts, whether wild or domestic, facilitates the persistence of the disease (Palmer et al. 2012). In such complex systems, the transmis­sion rate of the infection between species is largely determined by the spatial distribu­tion of susceptible hosts, the timing of contact between them, resource utilization patterns, and the frequency and intensity of interactions between these hosts at the human/livestock/wildlife interface (Renwick et al. 2007).

There seems to be a large variety of M. bovis strains circulating in the various susceptible hosts in Tanzania. In one study, 13 different pTBN12 RFLP types were encountered, of which the RFLP patterns reflected a high degree of relatedness (86%) between the dominant pTBN12 genotypes. There were 13 different spoligotypes found in this study, whose genetic relatedness was also high (79%). Their DNA profiles were also confirmed by IS986 RFLP, which revealed that these strains have 1-13 copies of IS986. Geographically, there is an overlap between pTBN12 RFLP and spoligotypes among strains isolated, and the diversity of the RFLP and spoligotype patterns observed probably reflects the extensive movement of pastoral cattle and contact with the different sources of the infection (Kazwala et al. 2006; Katale et al. 2015; Mwakapuja et al. 2013a, b). Spoligotype SB0133 is widespread and commonly occurs in cattle and wildlife in East Africa (Berg et al.

2011).

Intermingling of livestock and wildlife during grazing and at water sources might have contributed to the spread of M. bovis infection between livestock and wildlife. The role of each of these species in spreading the disease depends on the way of transmission, the abundance of each host, and interaction between hosts, but the actual situation is largely unknown (Nugent 2011).

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