Epidemiology of bovine tuberculosis in Tanzania: Systematic review and meta-analysis

Bovine tuberculosis (bTB) is an important animal disease in the world, with both economic and zoonotic implications. The disease is still endemic in developing world, such as Tanzania due to lack of rigorous bTB control measures. Despite its significant economic and public health importance in Tanzania, its epidemiological information is still inconsistent.

To address this, we carried out a systematic review and meta-analysis of published articles on bTB epidemiology in Tanzania from 1993 to 2024. Eleven epidemiological themes were examined: prevalence, distribution, incidence, transmission, risk factors, reservoirs, diagnostics, outbreaks, surveillance, genetic diversity, and control measures. Data were synthesized using narrative analysis and random-effects meta-analysis where sufficient homogeneous data existed.

Thirty-eight studies met inclusion criteria, with studies addressing bTB prevalence exhibiting high heterogeneity (I² > 90%) and the pooled prevalence of 1.0% (95% CI: 0.01-0.02) in both livestock and wildlife. Mbeya and Iringa regions experienced the highest prevalence, whereas Dodoma and Lake Zone had the lowest prevalence. Large herd size, communal grazing, older cattle, and proximity to wildlife were consistent risk factors. African buffaloes were the most important wildlife reservoirs, sharing strains with cattle at the livestock-wildlife interface. The Mycobacterium bovis spoligotype SB0133 was the most common lineage. The tuberculin test and culture were the most frequently used diagnostic approaches. Outbreak, incidence and surveillance studies were scarce and fragmented.

Although bTB is endemic in Tanzania, it has received little attention with geographical and thematic gaps still existing especially in incidence and surveillance. There is an urgent need for national strategy that integrates public health, livestock and wildlife systems. Also, molecular diagnostics, organized surveillance, outbreak investigations, and risk-based control measures should be among the priority areas.