New science on TB transmission

Bovine TB may be passed from badgers to cattle not through direct transmission, but through infected pasture and dung, new research shows.

A field study, carried out on 20 farms in Cornwall, aimed to show how the disease was passed to cattle from badgers - which is estimate to account for around 6% of herd infections. Professor Rosie Woodroffe, from the Zoological Society of London, led the new research. She said: "We know badgers can give TB to cattle, but we have never known how."

The breakthrough in understanding came by fitting 100 badgers with electronic collars. The researchers tracked 800 cattle while they were in badger territories, with the number of tracked days amounting to over 8,000.

Just once in 65,000 observations did a badger get within 10 metres of a cow and they preferred to be 50 metres away. Woodroffe continued: "We detected nothing [in way of interactions]. It looks most likely that the badgers are avoiding the cattle."

The discovery has implications for farming practices, in particular slurry spreading. It also explains why TB is so hard to control, even when badgers and cattle are culled, as the bacteria can survive in fields for months, says the story in today's Guardian (5th August 2016). Eradicating TB will require addressing this risk, the research suggests. You can read Damian Carrington's full story here