Publication Highlight: Whole-genome sequencing reveals genetic diversity and transmission dynamics of Mycobacterium bovis in South African wildlife
In a major new study, GenPath Africa colleagues Abisola Okunola, Johannes Loubser, Giovanni Ghielmetti, Rachiel Gumbo, Elizabeth M. Streicher, Pamela Ncube, Wynand J. Goosen, Robin M. Warren, Andre G. Loxton, Michele A. Miller, and Tanya J. Kerr from the South African Medical Research Council Centre for Tuberculosis Research and Stellenbosch University, investigated how animal tuberculosis (TB) spreads across different regions and species in South Africa. Their research provides the most detailed look to date at the genetic diversity and movement of Mycobacterium bovis (M. bovis) within complex wildlife ecosystems.
What is this publication about?
Researchers used whole-genome sequencing (WGS) to analyze 112 M. bovis isolates collected from 106 individual animals representing 12 different wildlife species across five South African provinces. By comparing the genetic codes of these samples, the team identified two distinct "family trees" (sub-lineages) of the bacteria and mapped their geographic clusters. The study found that very closely related strains were primarily found within single host species - particularly African buffalo - suggesting frequent transmission between animals of the same type. However, they also identified genetically similar isolates collected over a 25-year period, which suggests historical transmission events between different species.
Why is this important?
Animal TB is a significant threat to biodiversity and conservation in South Africa, yet how it moves through systems with many different animal hosts has been poorly understood. This study demonstrates that high-resolution genetic data is a powerful tool for tracing outbreaks and identifying potential sources of infection. It reveals that while some TB strains are geographically restricted to specific parks, others have expanded across broader landscapes over decades. Knowing these transmission patterns is essential for distinguishing between new outbreaks and long-standing endemic disease.
How can this make a difference?
The findings are vital for informing targeted management strategies to protect vulnerable and endangered species, such as the black rhinoceros and African wild dog. By identifying how the disease moves across species and landscapes, wildlife managers can develop better movement controls and integrated management strategies to mitigate spread. This research advocates for the expanded use of genomic surveillance to protect both South Africa’s unique biodiversity and the health of domestic animals and humans at the wildlife interface.
Abisola Okunola, Johannes Loubser, Giovanni Ghielmetti, Rachiel Gumbo, Elizabeth M. Streicher, Pamela Ncube, Anzaan Dippenaar, Wynand J. Goosen, Ana Marcia Sá Guimarães, Robin M. Warren, Andre G. Loxton, Michele A. Miller, and Tanya J. Kerr, "Whole-genome sequencing reveals genetic diversity and transmission dynamics of Mycobacterium bovis in South African wildlife." Microbial Genomics, 2026; 12: 001646. doi:10.1099/mgen.0.001646.
