Red squirrels are being struck down by leprosy

Leprosy has been identified as the mystery illness affecting endangered red squirrels at one of their last remaining homes in England.

Naturalists have been left baffled for the past 50 years after finding gruesome lesions on red squirrels living on Poole Harbour’s Brownsea Island in Dorset.

Laboratory tests on the corpses for known viruses have always come back clear to the bewilderment of wildlife experts.

But a study conducted by Professor Anna Meredith of the University of Edinburgh has revealed that symptoms such as fur loss and severe skin ulcers are a result of leprosy.

And after being contacted by the island’s nature reserve manager, Prof Meredith set up a makeshift laboratory in a bid to find out how the infection spread.

Red squirrel have been found with lesions

Brownsea is one of the last locations in England still to have red squirrels, with the vast majority of the 120,000 which remain in the UK living in Scotland.

Prof Meredith said the National Trust owned island, which is home to 200 of the animals, provides the ideal location for the three-year project as it is completely contained.

She said: “They are an icon of endangered British wildlife cherished both for their rarity and their beauty. But there is cause for concern in this red squirrel haven.

“Some have been spotted with a peculiar and disturbing illness – fur loss, swelling, ulceration – it is painful to even look at.

“These symptoms have been identified in a small number of squirrels for almost 50 years but the cause remained a mystery until a recent discovery 500 miles away.

Rex Red squirrels are already battling for survival

“Two years ago our team at Edinburgh University discovered that Scottish red squirrels had leprosy. We didn’t know it at the time, but we had also solved a decades old mystery on Brownsea Island.”

Prof Meredith now plans to humanely catch red squirrels, take blood and other clinical samples before microchipping them so that any evidence of the infection can be monitored over a long period.

She added: “It is really important that we try and understand a bit more because it’s never been described in squirrels before, and we want to know where they’re getting it from and how they are possibly spreading it to each other.

“Then we are taking the samples to test and work out what is going on here because they are an endangered species and we want to do the best conservation management we can.”

Prof Meredith stressed that although the leprosy impacts red squirrels in almost exactly the same it does on people, there is no threat on Brownsea Island to human health.

Rex Two red squirrels being affectionate

Chris Thain, who has lived on Brownsea Island for 16 years and is its nature reserve manager, said the number of red squirrels affected by the leprosy is small and those that do have it live a normal life and rarely die as a direct result.

He said: “This is only affecting a very small proportion of the red squirrels on the island, and it is important to stress that it presents no risk to human health.

“We think we can trace it back to the 1970s, but it could have been here for centuries.”

The population of red squirrels in the UK has fallen drastically in recent years to just 120,000 from a high of 3.5 million a few centuries ago.

Experts believe that this, in part at least, has been due to the introduction of non-native grey squirrels which compete with reds for food and carry a disease which is fatal to their native cousins.