Brownsea's squirrels: living with leprosy

Red Squirrel populations are being affected by leprosy

It’s a warm late autumn day on Brownsea Island in Poole Harbour. Dappled sunshine breaks through yellowing leaves. A red squirrel scampers up a beech tree. 

University vets have found a new threat to the quiet Dorset island's squirrels. The mammals are suffering from leprosy. 

And all the indications point to Brownsea’s squirrel population having lived with it for decades.

Brownsea Island seen from the air
Brownsea Island as seen from the air

Discovery

Anna Meredith is a professor of conservation medicine at the University of Edinburgh. 

Her team were the first to identify leprosy in red squirrels. Four years ago they noticed that squirrels in Scotland were showing signs of having the disease. 

Professor Meredith says: 'When I first realised the Brownsea squirrels had leprosy I was excited, but also concerned. The discovery told us that this disease that we'd seen in just a few Scottish squirrels was much more widespread and had been present for much longer than we originally thought.'

" A disease that we'd seen in just a few Scottish squirrels was much more widespread than we originally thought."
- Professor Anna Meredith, University of Edinburgh

Shock 

The news came as a shock to rangers on Brownsea Island, a place we care for with Dorset Wildlife Trust. 
 
Dr Angela Cott, our general manager for Brownsea Island, says: 'We’ve known for a long time that some squirrels on the island were suffering from a mystery disease. But tests on the squirrels were always inconclusive.'

A vet gives a red squirrel general anaesthetic
Squirrel being put under general anaesthetic

Effects

Leprosy causes swelling and hair loss to squirrels’ ears, muzzle and feet. It’s not yet known how the disease is passed between squirrels or how the disease arrived at Brownsea. 

Professor Meredith says: 'Because the Brownsea squirrel population has been contained on an island with this disease for so long it's an ideal study site.'

In September, University of Edinburgh vets spent a week on the island. They took blood, skin and hair samples for analysis before returning the animals to the wild.

A ranger looks on as Edinburgh squirrel vets take samples
Ranger looking on at researchers

Findings

The results from the four-year study will not be known for some time. But it’s hoped that the research study will help rangers on the island better understand how to manage the squirrel population. 

Angela Cott says: 'Many of our visitors come to see the red squirrels. They’re beautiful, characterful creatures. By working with the University of Edinburgh and Dorset Wildlife Trust, we’ll be able to look after the wild red squirrels for visitors to enjoy in years to come.'