Following on from the findings of research published by Durham University professor Peter Atkins in February, a new study from the Royal veterinary College suggests badgers and cattle with TB rarely meet.

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The findings raise some questions about the government's bovine TB eradication policy, a large part of which is centred on culling badgers as a means of reducing the instance of bTB.

In February, Durham's Professor Atkins suggested that "bTB in badgers is a spillover disease from cattle rather than an endemic condition and probably does not persist over lengthy periods." He said research did not reveal evidence of "interspecies transference… on the necessary scale" to justify seriously considering culling badgers.

He also pointed out that "No one has yet proved definitively which direction the infection travels between species. The Randomised Badger Culling Trial, which ran from 1998-2006 indicated complex, interwoven patterns of infection and concluded badger culling was unlikely to be effective for the future control of bTB."

On Wednesday, researchers from the RVC said that, contrary to popular belief "it may be rare for bovine TB to be passed on through [cattle and badgers] meeting each other on pasture." Research by RVC and government agency FERA, published this month in the journal Epidemiology and Infection, suggests the two species may even actively avoid one another.

However, the researchers did say that indirect contact may still play a part in infection.

RVC experiment reveals little badger-cattle interaction

As part of the study, researchers fitted automated high-tech proximity loggers to animals and placed base stations at badger latrines located on pasture in an area of south-west England which is densely populated by badgers. They measured direct and indirect interactions between animals over a period of 12-months.

The study showed that direct interactions (animals coming within 1.4 metres of one another) between badgers and cows at pasture were very rare, with only four out of over 500,000 animal-to-animal contacts recorded between the two species. Indirect interactions (visits to badger latrines) were far more frequent, however, and the researchers suggested "indirect contacts might be more important than direct in terms of disease transmission at pasture."

During the study, half of the badgers tested positive for TB, which is endemic in cattle in parts of Western England and Wales. As well as infecting cattle, the disease can also spread to other animals, including badgers, deer, cats, pigs and humans.

Bovine TB spreads through droplets in the air, or through ingestion of infected materials. The researchers said, "it has not previously been known where, when or how often transmission occurs, [though] previous research suggests that TB infection passes both from badgers to cattle and from cattle to badgers."

Dr Julian Drewe from the Royal Veterinary College who led the study explained the findings, "Direct contacts between badgers and cattle at pasture are surprisingly rare, despite ample opportunity for interactions to occur, suggesting that the two species may be ignoring or even actively avoiding one another. The study was conducted in an area with a high badger population, so it is likely that such direct contact will be even less frequent in areas of the country where there are fewer badgers."

Speaking to Farming Online on Wednesday, Dr Drewe explained the significance of the investigation. He said, "The high number of indirect contacts may pose a greater risk for disease to spread than previously thought. Similarly, the rarity of direct contacts between badgers and cattle suggests there is limited opportunity for disease to spread via direct interactions between the two species.

"Taken together, these findings indicate that focusing on the role of indirect interactions in TB transmission may help to identify effective ways to manage this disease. We suggest that fencing off badger latrines on pasture may make a helpful contribution to TB control."

He added that future work should focus on means of limiting indirect interactions between badgers and cattle, including not only at latrines, but also away from pasture, such as in or around farm buildings.

Dr Drewe stated "This study's findings have no direct implications on the culling policy. Indirectly, they offer evidence for alternative methods that may contribute to disease management." He also explained the next step for research in the area, "A larger scale study of contact patterns between badgers and cattle is currently being undertaken across several farms, to see if the patterns identified in this study hold true over a larger area."