21 October 2013 by Sarah Griffiths
Disrupted social structures in setts linked to higher rates of infection British scientists have shown that the social lives of badgers are related to their risk of infection with bovine tuberculosis (TB)
Researchers at the University of Exeter built a network of contacts across a population of badgers and analysed patterns of infection
They found TB-infected animals were less well-connected to their own groups but infected animals spread the disease between groups
Culling badgers may actually help spread disease because it disrupts the social links in setts, according to a new study. British scientists have shown that the social lives of badgers are related to their risk of infection with bovine tuberculosis (TB). TB-infected animals were less well-connected to their own groups than uninfected badgers so disrupting badger societies could unbalance the creatures’ natural way of keeping the majority of setts healthy and TB-free, the report suggests.
Culling badgers might help spread bovine tuberculosis because it disrupts the social links in setts, according to a scientists who have shown the social lives of badgers are related to the risk of infection with the disease
Researchers at the University of Exeter and the AHVLA’s National Wildlife Management Centre fitted ‘electronic proximity collars’ to 50 wild badgers that automatically tracked their social contacts.
PhD Student Nicola Weber built a network of contacts across the population and analysed patterns of infection. She found that TB-infected animals were less well-connected to their own groups than uninfected badgers, but infected individuals formed important links for the flow of infection between groups.
The research, which is published today in the journal Current Biology, suggests this unusual social arrangement may stabilise the spread of TB infection across the population. Professor Robbie McDonald from the university, said: ‘This study has revealed an important link between social networks and TB infection.
In 2012, more than eight million tests were conducted on cattle and 38,000 cattle were slaughtered to control TB. The disease costs the UK taxpayer around £100m every year as the testing and resulting compensation are costly
‘Infected animals were likely to be less important for spread within groups while at the same time being more important for spread between groups. Social stability is thought to mitigate disease spread, perhaps by maintaining the distinctive position of these individuals ‘Culling badgers perturbs social structures and we think our findings may help understanding of so-called “perturbation,” where culling has been linked to increases in TB in badgers.
He said that curbing TB infection in wildlife remains a challenge but ‘vaccniation has the potential to disrupt disease flow, without perturbing social network structures.
Tuberculosis infection in cattle is a major animal health challenge in the UK and Ireland.
Professor Robbie McDonald said: ‘Culling badgers perturbs social structures’. He said vaccination has the potential to disrupt disease flow, without perturbing social network structures. Here, Queen guitarist Brian May who is founder of Save Me, joins a rally in Bristol against the proposed badger cull.
In 2012, more than eight million tests were conducted on cattle and 38,000 cattle were slaughtered to control TB.
TB costs the UK taxpayer around £100m every year as the testing and resulting compensation are costly.
The study of the spread of disease through analysis of social networks has applications beyond badgers.
The network analyses involved are similar to those used in people and so these techniques can be used to learn about how infection is transferred in a range of behaviourally complex hosts including humans, livestock and wildlife.
CAMPAIGNERS CLAIM CULL COSTS £2,200 FOR EVERY BADGER KILLED
The controversial badger cull has fallen so far short of its target that every animal killed has cost taxpayers more than £2,000, it is claimed. Only 708 badgers, or 30 per cent of the population, have been killed in Gloucestershire, falling far short of the 70 per cent target. Earlier this month it was reported that 850 animals have been killed in Somerset – the other area where the cull pilot is being carried out – far fewer than the aim of 2,100.
The overall costs of the two culls, including policing animal rights protesters, is estimated by campaigners at some £3.5million, so with a total of 1,558 dead animals, this works out at £2,246 per badger.
In contrast, vaccinating badgers against bovine tuberculosis in Wales was less than a third of the cost at £662 per animal.
Campaigners warned that the inability to meet targets could increase the spread of TB in cattle.
Speaking last week, Dominic Dyer, of charity Care for the Wild, said: ‘I don’t know how they can possibly kill enough badgers in the next three weeks in either zone to reach the total they want. That means scientifically the cull can’t possibly have any positive impact on bovine TB – and will most likely make it worse.
Experts have said that at least 70 per cent of badgers in an area must be killed in order to limit bovine TB – meaning that costs could spiral further if the cull is unsuccessful. Environment secretary Owen Paterson denied the project was a failure but confirmed the cull companies would be seeking an eight-week extension so they could reduce animal numbers further.