How can DAFM best make use of whole genome sequencing to improve the effectiveness of the TB eradication programme?

Whole genome sequencing (WGS) is a technique used to determine the complete DNA sequence of an organism's genome. In the context of bacterial pathogens, such as the causative agent of bovine tuberculosis (Mycobacterium bovis), WGS offers insights into the nucleotide sequence variations that arise due to mutations during bacterial replication. By tracing these mutations, researchers can differentiate between bacterial strains and assess the historical divergence and relatedness of strains. The Irish Department of Agriculture, Food and the Marine (DAFM) sought an opinion from the TB Forum scientific working group on the utility of WGS in the bovine tuberculosis (bTB) eradication programme. Through various case studies in regions such as Cumbria and Woodchester Park, UK, WGS provided insights into the directionality of transmission between species, revealing complex interplays between cattle, badgers, and deer. For instance, in Cumbria, cattle-to-cattle transmission dominated initial phases of an outbreak before the bacteria established in the local badger population. In contrast, studies in other regions suggested varying roles for wildlife in the transmission and persistence of M. bovis. WGS will enhance the efficacy of the BTB Eradication Programme in Ireland, and can be harnessed to attribute infection sources, identify transmission pathways, and quantify transmission rates across species. A major project in Ireland, BTBGenIE, funded by DAFM and led by University College Dublin, is already integrating WGS with traditional eradication and surveillance activities. It is essential that M. bovis genome sequence data are shared with the national and international scientific community in a routine and contemporaneous manner, to maximise the opportunities for analysis and public good arising from WGS studies. This is especially relevant for Northern Ireland considering the movement of cattle between Northern Ireland and the Republic of Ireland.