Researchers fitted GPS collars to cattle and badgers to to track their movements with interesting results.
Cattle and badgers rarely come in to direct contact and bovine TB is therefore spread by the fact both species use the same fields where infected faeces and urine can be found.
Lead author Prof Rosie Woodroffe, of the Zoological society of London, states within the study that the findings have ‘important implications for TB control’.
Taking place across 20 TB-infected farms in Cornwall between May 2013 and August 2015, 421 beef and dairy cattle and more than 100 badgers were fitted with GPS collars to track their movements.
As a result, the researchers said they detected no occasions when cattle and badgers came within 1.5 metres of each other, that being the distance needed for ‘direct aerosol transmission of M. Bovis’.
The paper goes on to state: “Our ﬁndings have important implications for TB control. If, as our results imply, M. bovis transmission between badgers and cattle occurs primarily through the shared environment, infection risk might remain for some time despite the removal of individual M. bovis-infected badgers or cattle.
“Such environmental persistence might help to explain why widespread badger culling reduced cattle TB only gradually (Donnelly et al. 2007), why some herds experience repeated TB incidents (Conlan et al. 2012), and why cattle TB remained clustered even after culling had dispersed infection clusters in badgers (Jenkins et al. 2007).
“Moreover, the possibility some proportion of cattle-to-cattle transmission might occur through the environment is worth further consideration because, while TB test-posi-tive cattle are compulsorily quarantined and slaughtered, contaminated pasture, manure, or slurry are seldom managed as potentially infectious.
“Studies of the distribution, persistence, and infectiousness of environmental M. bovis would therefore be warranted to help reﬁne TB control strategies.”
A Defra spokesman said: “This paper provides further evidence that badgers and cattle contribute to the spread of bovine TB in areas where the disease is rife. Previous independent research has concluded TB spreads within and between populations of badgers and cattle, and that spread from badgers to cattle is an important cause of herd breakdowns in high-incidence areas.
“Our comprehensive strategy to beat bovine TB includes tighter cattle controls, good biosecurity and badger control in areas where the disease is widespread, and a number of measures are in place to prevent the spread of infection.
“These include frequent testing and rapid removal of infected cattle, pre- and post-movement testing and wildlife proofing of high risk units. To reduce the risk of cattle to cattle transmission from contaminated environment, farmers are required to carry out cleaning and disinfection and to keep cattle out of fields grazed by reactors for two months after their removal. There are also rules about the use of manure and slurry on infected farms to mitigate the risks associated with their spread.”
Catherine McLaughlin, NFU chief adviser (animal health and welfare), said: “The role played by badgers in the spread of bovine TB is well known and widely accepted. Badgers are recognised as a significant wildlife reservoir of the disease in areas where it is endemic.
"Research has shown that badgers could contribute to up to 50 per cent of cattle herd TB breakdowns in areas where the disease is rife and that up to one in three badgers in these areas have bTB.
“We have always said we must use all options available if we are to stand a chance of controlling and eradicating this devastating disease. This includes cattle testing; cattle movement controls; and on-farm biosecurity. It also includes badger vaccination, once a vaccine is available again, in areas on the edge of the disease spread; cattle vaccination when available; and culling of badgers in areas where bTB is rife.
“The Government’s 25-year TB eradication strategy, which is based on the best available evidence and scientific advice, is the first comprehensive plan of its kind we have ever had to tackle bTB in England and we believe it gives us the best chance of controlling and eradicating this disease.”