Badgers Responsible For Over Half of TB in Heavily Infected Areas14 October 2013
UK – Over half of all bovine tuberculosis (TB) cases in cattle in heavily infected areas are caused by badgers, a cull analysis at Imperial College London has found.
Epidemiologists have concluded a review of data from the Randomised Culling Trial stating that badgers were responsible for 52 per cent of cases.
However, less than six per cent of transmissions are direct from badger to cattle, with onward transmission through the herd accounting for the remainder.
The study consisted of two data analyses from the Randomised Badger Culling Trial (RBCT), which ran for seven years between 1998 and 2005.
A conservative ‘robust minimum value’ of 38 per cent was given by Professor Christl Donnelly and Dr Pierre Nouvellet of the Department of Infectious Disease Epidemiology.
The revelation strengthens the link between badgers and bovine TB, although Professor Donnelly said this does not make a solution easier to come by.
“These findings confirm that badgers do play a large role in the spread of bovine TB," commented Professor Donnelly. "These figures should inform the debate, even if they don’t point to a single way forward.”
The complication of moving the disease elsewhere when cage-trapping and culling badgers was discussed.
The paper cited a 2 kilometre margin around the culling area in which TB incidence was shown to increase when culling was on-going.
In the paper The Contribution of Badgers to Confirmed Tuberculosis in Cattle in High-Incidence Areas in England, Professor Donnelly stated: “Although an average overall contribution from badgers of at least 38 per cent indicates their importance in the disease system, in areas analysed it does not indicate how this contribution might best be limited.”
To view the full report The Contribution of Badgers to Confirmed Tuberculosis in Cattle in High-Incidence Areas in England - click here.