New study maps the genetic landscape of bovine TB across Wales

Credit: Sergio Arteaga, Pexels

Bovine tuberculosis is evolving in different ways across different regions in Wales, according to the most detailed analysis of the bacterium conducted to date.

One of the most significant animal health challenges facing Wales, bovine TB affects cattle health and farm businesses and places considerable emotional, social and financial pressures on farming communities.

By understanding how the bacterium spreads within and between cattle and wildlife populations and changes over time, researchers can help develop more effective ways to control the disease.

The latest research, led by scientists at the Sêr Cymru Centre of Excellence for Bovine Tuberculosis at Aberystwyth University, used whole-genome sequencing to analyse the DNA of the Mycobacterium bovis bacterium.

Published in Nature Scientific Reports, the study examined 379 samples collected from infected animals across Wales in 2021.

The research found that different regions of Wales contain genetically distinct strains of the bacterium, suggesting that it is evolving differently in different regions of the country in ways that may influence how it survives and interacts with its hosts. 

The research also identified strains not normally found in Wales, potentially linked to cattle movements from outside the country.

The findings provide important clues about the biology of the disease and highlight areas for future investigation.

Lead author Dr Amy Healey, Lecturer in Ecology at Aberystwyth University, said:

“By analysing the genome sequences of Mycobacterium bovis samples, we were able to build the most detailed picture to date of the bacterium's genetic diversity in Wales. Our findings highlight the importance of understanding disease transmission at a local level and demonstrate how genomics can help us move beyond tracking disease transmission and begin to understand the biology of the pathogen itself.”

Co-author Dr Amanda Gibson, UKRI Future Leaders Fellow and Lecturer in Innate Immunology at Aberystwyth University, added:

“As well as identifying distinct genetic clusters and evidence that some strains may have been introduced from outside Wales, we uncovered genetic differences that could influence how the bacterium survives, adapts and interacts with its hosts. While further research is needed to understand the significance of these variations, our findings provide the most detailed picture yet of the M. bovis population in Wales. This valuable resource will help researchers investigate why bovine TB persists and support the development of more effective disease-control strategies in the future.”

The study used whole-genome sequencing, a technique that provides far greater genetic detail than earlier methods used to characterise the bacterium.

The research was carried out by scientists from Aberystwyth University in collaboration with colleagues from the Animal and Plant Health Agency and Queen's University Belfast. It was funded by the Sêr Cymru II project held by Professor Glyn Hewinson that was responsible for the establishment of the Sêr Cymru Centre of Excellence for Bovine TB.  The sequencing of M. bovis isolates was funded by the Department for Environment, Food and Rural Affairs along with the Welsh and Scottish Governments.

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