U.K. expands kill zone for badgers in fight against bovine TB, sparking controversy

The United Kingdom will triple the number of badgers killed in its campaign to eradicate a strain of tuberculosis (TB) that strikes cattle. As many as 33,841 badgers could be shot over the next year, the Department for Environment, Food and Rural Affairs announced yesterday. Wildlife advocates are upset at the increased slaughter, and scientists are skeptical about the chances of success. “It is deeply disappointing,” said Rosie Woodroffe, an ecologist with the Zoological Society of London.

Bovine TB has been spreading for 2 decades in the United Kingdom, and England has the highest incidence in Europe. There is no threat to human health, because pasteurization kills the bacteria in milk. Cattle herds are regularly checked for the disease, and when infections are detected, the herd must be slaughtered. Last year the toll reached 29,000 animals. The disease enters herds through the shipping of undiagnosed cattle, and from badgers, which are the main reservoir of the disease in wildlife.

The government’s 25-year strategy to eradicate bovine TB relies on restricting transport of cattle from disease hot spots and vaccinating or killing badgers. Badger culls began in 2013 in Somerset and Gloucestershire, and now cover 10 areas. Eleven more areas are being added now, each covering an average of 489 square kilometers. A preliminary analysis of the first 2 years of culling, reported last month in Ecology and Evolution, cautioned that the data were limited and it would be “unwise” to generalize about how effective the policy has been so far.

Badger culling is a double-edged tool, according to an 8-year experiment that began in 1998. When done effectively, it can reduce bovine TB inside the control zone, but incidence is likely to increase up to 2 kilometers outside. That appears to be because some badgers leave the control zone, as a result of disruption to their social groups, and spread the disease.

Tim Coulson, a zoologist at the University of Oxford in the United Kingdom, participated in the independent expert panel that the oversaw the experiment. He calls the expanded cull “contrary to scientific understanding.” The trial culls showed the difficulty of achieving the necessary 70% reduction in badger population needed to reduce the risk of spreading disease to cattle. “My interpretation of this policy is that the government thinks it is better to be seen to be doing something, rather than to do nothing at all—even if it risks making the problem worse.”

The U.K. government’s chief veterinarian, Nigel Gibbens, yesterday called the culls “the best available option” for controlling the disease and said they should be rolled out to more of the country. Vaccination of badgers will begin again in 2018, after a 2-year pause due to a vaccine shortage, farming minister George Eustice said.