Tuberculosis in cattle and badgers passes between members of the same species at least twice as often than between cow and badger, a study has found.
Researchers analysing genetic data from the bacteria that causes the disease also found that cattle are approximately 10 times more likely to catch TB from badgers than badgers are to catch it from cattle.
Using data collected over a 15-year period from an undisturbed population of badgers in Woodchester Park,
Gloucestershire and nearby farms, the study provides the first direct evidence of transmission between badgers and cattle.
The researchers analysed the entire genetic make-up of the bacteria from 230 badgers and 189 cattle, a process known as whole genome sequencing.
This was combined with information on where the cattle and badgers lived, when they were infected, and whether they could have had contact with one another.
The work was led by experts from the University of Edinburgh, with collaborators from institutions including the Animal and Plant Health Agency, the University of Glasgow and University College Dublin.
Rowland Kao, Professor of Veterinary Epidemiology and Data Science at the University of Edinburgh, said: “Current approaches to controlling bovine tuberculosis only discriminate at a very coarse, regional level between areas where badgers are more likely to be involved in infecting cattle from areas where they are not.
"This work identifies genetic signatures that could guide the interpretation of similar data if collected in other, less-intensively studied areas.
“This would allow for a more targeted control of tuberculosis in cattle and badgers, aiding efforts to control the disease and reduce the impact on the badger population.”