In a bold move by one of the country’s leading critics of the badger cull, Brian May convened vets, academics, scientists and civil servants in London to discuss new insights into the scourge of bovine TB in the UK. Olivia Midgley reports.
Huge amounts of time, energy and money have been wasted on the polarised debate surrounding bovine TB, former Queen guitarist and anti-badger cull campaigner Brian May said as he opened the TB symposium at London’s Imperial College.
Founder of the Save Me Trust, ardent animal rights campaigner Dr May organised the event to encourage all sides of the debate to come together and ‘open a new area of cooperation in the fight against this pernicious pathogen’.
“By bringing so much wisdom together in one room we hope to take a step towards establishing the whole truth about bovine TB,” Dr May said.
Delegates, paying £130 a ticket, listened to wide-ranging reports from more than 20 speakers considered to be leaders in research into the transmission of bovine TB, its effects on cattle and badgers, and methods to control its spread.
So what do we actually know?
Several speakers said budgetary constraints were holding back both scientific research into the disease, preventing the discovery of effective solutions.]
Prof Ian Boyd, chief scientific adviser at Defra, highlighted the ‘trade-offs’ facing Government, between spending money on animal and human disease and said, faced with a choice, research to benefit humans would always win.
“We have choices as a Government on what we spend money on,” said Prof Boyd, highlighting how about 40,000 people die from air pollution each year, opposed to the 29,000 cattle slaughtered due to bTB.
“This gives some insight into the kind of trade-offs seen in Government in terms of policy. It is virtually the same in Defra for every problem it faces.”
He also said ‘in some eyes’, the UK Government subsidised and in some way ‘tolerated’ bovine TB by compensating farmers when cattle were destroyed.
UK chief veterinary officer Nigel Gibbens said the question of how much the cattle epidemic was down to badgers was ‘one of the most difficult questions to model, let alone answer’.
A 2013 research paper by Christl Donnelly and Pierre Nouvellet estimated at the start of the Randomised Badger Culling Trials (RBCT) in high incidence areas:
“While it is difficult to quantify, badgers are playing a large role in the epidemic in the high risk area and there needs to be wildlife intervention to achieve OFT status for all England,” said Mr Gibbens.
Mr Gibbens said spread between cattle in a herd could occur, but this was ‘relatively inefficient’. Badger-to-cattle transmission could be primarily indirect and at pasture, which was the most difficult route to prevent. He said the bacteria Mycobacterium bovis (M. bovis) was frequently found in badger faeces.
Prof Rosie Woodroffe, Institute of Zoology, London, said her team’s monitoring of cattle and badger contact over 2,914 nights had found zero contact.
However, she said there were ‘masses of opportunities’ for transmission to happen in the wider environment, without direct contact between the animals.
“We have to remember TB is not gone when the infected badger is gone.”
Richard Sibley of West Ridge Veterinary Practice told the symposium he was one of the few people who ‘make money’ from bovine TB, leading a team of 14 which mostly dealt with cattle in the South West ‘TB hotspot area’.
He said while his practice tested thousands of cattle each year, he was unable to treat them.
He told delegates he would like to see a test which was ‘part of the plan’, adding a test should determine the difference between an animal being ‘infected’ and ‘infectious’.
Mr Sibley, who is also the director of myhealthyherd.com, highlighted the importance of good biosecurity and creating a risk profile for each herd.
Prof James Wood, infectious disease epidemiologist and head of the University of Cambridge’s veterinary school, said with current tests being ‘quite imperfect’ it was vital to ‘use all the tools we have while seeking new ones’.
He said: “We need improvements to the skin test. We need more sensitive tests so we can detect more infection [and to differentiate between infection and vaccination].”
He said the blood test was effective at finding early infections but warned against using it routinely as it had a high percentage of false positives.
Slaughterhouse surveillance was assumed to be 100 per cent specific.
M. bovis can survive in soil, meaning it can be transmitted to humans and animals.
Prof Liz Wellington, University of Warwick, said research from badger and cattle faecal sampling had showed the bacterium could survive in soil and be a risk to animal and human health for up to one year. She said it meant faecal sampling was an ‘effective way of surveying how prevalent M. bovis was on a farm’.
Christl Donnelly, a member of the Krebs Committee in 1997 whose report led to the establishment of the Randomised Badger Culling Trials (RBCT), said a badger cull confined to a small area could be more detrimental to the spread of TB.
This is due to the perturbation effect, whereby infected badgers can spread the disease when they are disturbed by culling.
She pointed to research which showed outside proactive culling areas, incidents of TB in cattle were 29 per cent higher than on farms up to 2km outside no culling areas, adding, ‘an extensive cull or no cull at all would be best’.
Animal and Plant Health Agency (APHA) scientist Dr Graham Smith agreed there was evidence to suggest badgers went ‘to and fro’ before deciding to settle.
He added: “They move from social groups and then move back in, so there is risk of spreading more disease.”
He also highlighted annual badger mortality rate was about 33 per cent. With such a large turnover in the badger population, the challenge of controlling bTB cases was even greater, he said.
Dr Freya Smith, APHA, said global supply issues with the BCG vaccine had halted most badger vaccination schemes, for example in Wales.
She said her department had been working on a peanut-based ‘bait’ to encourage badgers to ingest the vaccine, rather than being cage trapped and injected.
James O’Keefe, Department of Agriculture, Food and the Marine (DAFM), said from 1965-2000, about 30,000-40,000 cattle had been removed from the national herd each year after testing positive for bTB.
“We realised the problem was being spread by TB-infected badgers,” said Mr O’Keefe, adding a national badger culling programme in areas where the disease was endemic had destroyed an average of 6,000 badgers each year.
Densities were maintained at about 0.5 badgers per sq.km.
“By 2010 we were convinced badger removal reduced the risk of bovine TB in cattle herds,” he said.
DAFM was also running a badger vaccination programme on 5 per cent of agricultural land, though farmers were concerned this would be less effective than culling.
In Northern Ireland, a badger test, vaccinate or remove approach had yielded good results, said Dr Fraser Menzies, Department of Agriculture, Environment and Rural Affairs.
He said the trial, which started in 2014 and cost about £1 million each year, had universal support from farmers, vets and wildlife groups.