SCIENTISTS are using sheep as moorland “tick traps” in an experiment that could tackle a killer virus that preys on hill walkers and ramblers.

The number of Lyme disease cases has risen tenfold since records began 20 years ago — the latest available tally, for 2003, reported 340 cases and six deaths.

However, estimates for the past two years suggest that the number of cases may have risen dramatically to about 2,000 a year as a result of Britain’s increasingly mild winters.

Now scientists have come up with a novel weapon to beat the ticks — they are using the humble sheep as a woolly trap to “mop up” the insects.

In experiments being carried out on Britain’s uplands, sheep are being given tick treatments similar to those used on pet dogs and cats. Ticks are then attracted to the sheep and killed in huge numbers.

Hikers have the glorious 12th and grouse shooting to thank for the breakthrough — the scientists were working for the Game Conservancy Trust on ways of protecting grouse chicks from the ticks.

Morag Walker, of the Game Conservancy Trust, said the benefit for ramblers was a happy but unintended consequence. “Grouse numbers on the heather moors are precarious and one of the many problems they face is a disease called ‘louping ill’ caused by ticks,” she said.

“There has been a huge increase in tick numbers in recent years and that would appear to be connected to global warming. We have reports of tick infestations starting as early as March and going right through until the end of October, when they used to be confined to the months of June, July and August.

“Our scientists came up with the idea of using sheep, which are themselves constantly prey to ticks, as a delivery system for tick insecticide. They’ve used sheep as tick mops to literally clean the insects off the moors with great success in trials in Scotland and Yorkshire.

“We’re hoping this will take the battle to the tick and dramatically hit their numbers on upland areas. It seems that what’s good for grouse is good for humans, too, in this case.”

Cases of Lyme disease are on a steep upward curve. Without treatment with antibiotics, one in 10 people infected can expect to die with severe inflammation of the heart. Some sufferers report a red “bull’s eye” shaped mark on the skin radiating around the tick bite.

Scientists say that one in every three ticks carries Lyme disease, so a decrease in tick numbers could have a significant effect on reducing the illness in humans.

Dave Newborn, a senior scientist in the charity’s upland research group, said tackling the tick was essential to the survival of commercial grouse moors: “There was an unprecedented grouse population crash last year and they are seriously affected by the continued escalation in tick numbers.

“Our research has shown that louping ill, a viral disease, can kill up to 80% of red grouse chicks infected. In 1985 around 4% of grouse chicks had ticks, but by 2003 this figure had risen to 92%. That’s a huge increase that affects birds and humans.”

Ticks begin their life cycle as tiny black creatures not much bigger than a pinhead that can attach themselves to warm-blooded creatures that brush against the heather or bracken in which they live.

They grow rapidly to become grey-coloured creatures the size of a pea and gorge themselves on the blood of their hosts.

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