RESEARCHERS are set to spend four years on Brownsea Island learning more about red squirrels with leprosy.

The project aims to find out how the disease affects and is passed between the red squirrels and how conservationists can control its spread.

Leprosy was identified in red squirrels for the first time in Scotland in 2014, though it is thought to have been in the population for centuries.

Post-mortem examinations have revealed it is also affecting squirrels on the Isle of Wight and Brownsea Island, in Poole Harbour, Dorset, which are among the few spots in England that red squirrels are still found.

Numbers of the animal have fallen drastically to around 140,000 in the UK, with most of the population in Scotland.

The main threats to red squirrels come from habitat loss and the introduced American grey squirrel, which out-compete their native cousins and spread a disease ''squirrelpox'' which is fatal to the reds.

The new research project focusing on leprosy will take place on Brownsea Island, where the disease is thought to have been for many years but only recently diagnosed.

Little is known about how the leprosy bacteria, which causes swelling and hair loss to the ears, muzzle and feet, is spread among red squirrels.

Angela Cott, property manager of the National Trust's Brownsea Island, said: "We have known that squirrels have got some kind of disease for decades. We've been seeing them for many years with little swellings on their ears and noses which makes them look like they have little 'cauliflower ears'.

"We have a very thriving population on the island and they have had this for possibly decades. We have about 200 squirrels on the island and only a few of them are ill."

She added that the risk to humans is 'very minimal' with the last known diagnosed case of leprosy in the UK having taken place in 1798.

She added that the risk can be made even smaller by following some basic hygiene practices such as people washing their hands before eating.

Dr Simon Cripps, chief executive of Dorset Wildlife Trust, said: "We've taken expert advice and it is going to be very difficult to treat in the wild. As with humans, they need three treatments over six months, otherwise we could be dealing with antibiotic resistance which would be terrible.

"It's possible that leprosy has been in the squirrels on the island for millennia, we just don't know."

Humane traps will be used to capture the squirrels for health checks, taking blood and other clinical samples before returning the mammals to the wild.

The island location of the study will enable researchers to examine the impact of leprosy on the squirrels in a contained environment.

Lead researcher Professor Anna Meredith, of the University of Edinburgh, said: ''The aim of our study is to find out how and why red squirrels catch leprosy, and how it affects individuals and populations.

''This disease appears to have been in squirrel populations in Scotland and England's south coast for some time.

''With this research we aim to help conservationists better understand the disease in this iconic species.''

The risk to humans from the disease is negligible, the wildlife experts add, and Brownsea Island will remain open to the public while the research is going on.