In a pioneering new study, GenPath Africa colleagues Rachiel Gumbo, Tanya Kerr, Robin M. Warren, Michele Miller, and Wynand Goosen from Stellenbosch University have confirmed that cattle can naturally shed live tuberculosis bacteria in their waste. Their research provides rare field-based evidence that challenges traditional views on how animal tuberculosis (bTB) spreads.

What is this publication about?

Researchers investigated the presence of viable Mycobacterium bovis (M. bovis)—the primary cause of bovine tuberculosis—in faecal samples collected from 79 free-ranging domestic cattle in rural KwaZulu-Natal, South Africa. The team processed the samples in high-containment laboratories using mycobacterial culture and advanced molecular tools like GeneXpert MTB/RIF Ultra and spoligotyping to identify the specific strains of bacteria present. They successfully isolated live, infectious M. bovis from two animals and detected bacterial DNA in several others.

Why is this important?

Traditionally, it was believed that animal tuberculosis was spread almost exclusively through the air when an infected animal breathed or coughed on another. This study provides some of the first definitive evidence that live bacteria are also shed through faeces under natural field conditions. This means that cattle waste can contaminate shared grazing lands, soil, and water sources, creating a significant "environmental reservoir" for the disease. The study also identified other environmental mycobacteria, highlighting the complexity of accurately diagnosing TB in regions where many different types of bacteria coexist.

How can this make a difference?

These findings demonstrate that current TB control programmes, which often focus only on lung-related transmission, may be overlooking a critical route of infection. By recognizing faecal shedding as a transmission pathway, health officials can develop more effective One Health strategies that account for environmental contamination. This is especially vital in communal farming areas where livestock, wildlife, and humans frequently interact. Ultimately, this research supports the development of better surveillance and control measures to protect both animal health and public safety from zoonotic tuberculosis.

Rachiel Gumbo, Tristen Lourens, Deborah M. Cooke, Tanya J. Kerr, Robin M. Warren, Michele A. Miller, Giovanni Ghielmetti, and Wynand J. Goosen, "Isolation of viable Mycobacterium bovis from faeces of naturally infected free-ranging rural domestic cattle (Bos taurus)." Journal of Applied Microbiology, 2025; 136(12): lxaf281. doi:10.1093/jambio/lxaf281