Leprosy in Britain’s red squirrels is being caused by the same species of bacteria that killed medieval humans, it has been discovered.
Experts from The University of Edinburgh’s Royal (Dick) School of Veterinary Studies found one of the strains – affecting squirrels on Brownsea Island, off England’s south coast – shares close similarities with a strain discovered in the skeleton of a leprosy victim buried in Winchester 730 years ago.
The strain is also similar to one endemic in armadillos in southern states of the US.
Researchers tested 25 samples from red squirrels on the island and found that all were infected with the bacteria Mycobacterium leprae, though not all showed signs of the disease.
Scientists say their findings suggest leprosy has affected red squirrels on Brownsea Island for centuries, but stress the chances of people catching the disease are low.
Threat level uncertain
Red squirrels in other parts of England, Scotland and Ireland are also affected by leprosy. The study found these animals were infected with a species of bacteria called Mycobacterium lepromatosis. DNA analysis revealed this strain is similar to those found in human cases of leprosy in Mexico and the Caribbean.
The international team – led by the University of Edinburgh in collaboration with the École Polytechnique Fédérale de Lausanne – collected samples of the bacteria during postmortems carried out on red squirrels from each of the locations.
Researchers said it is unclear whether leprosy poses a significant threat to the future of red squirrels. They have launched a major study on Brownsea Island to study the disease. The findings are published in the journal Science.