Are Viking Squirrels to Blame for Infecting England with Leprosy?

It’s possible, say researchers who found that medieval strains of the disease may have come to Great Britain in the rodents’ fur and meat

Red Squirrel
Fear not: Though it was recently found that red squirrels can harbor the leprosy bacteria, there hasn't been a single confirmed case of the disease in the UK in 200 years. Wikimedia Commons

In medieval England, leprosy was one of the most dreaded and horrifying maladies one could contract. Not only did it lead to painful nerve damage and loss of extremities and entire limbs, but victims suffered social isolation and were often forced to live in leper houses or hospitals on the edges of town. Now, reports Maev Kennedy at The Guardian, a new study finds an unlikely factor that may have driven the spread of leprosy in Great Britain: a robust trade in the meat and fur of Scandanavian red squirrels. Yes, squirrels.

Researchers examined the remains of "the Woman from Hoxne," a medieval leprosy victim discovered in a back garden in East Anglia in the late 20th century. According to a press release, the skull had some telltale signs of leprosy, also known as Hansen’s disease, including the crumbling of the nose bone. The researchers used radiocarbon dating to determine that the woman lived between 885 and 1015 A.D. They also examined small shavings from the skull to find that they contained DNA from Mycobacterium leprae, the bacteria that causes leprosy.

Analysis of the bacteria shows that was from a strain found previously in skeletons discovered in East Anglia dating between 415 and 445 A.D., suggesting that East Anglia was a hot spot for the disease for centuries before it became prevalent in other parts of Great Britain.

That same strain of leprosy is also known to have infected people living during the same time period in Denmark and Sweden. The BBC reports that ports in East Anglia were known for importing squirrel fur from Viking controlled Scandinavia, raising the possibility that the disease came to East Anglia with the scythe-tailed rodents. The research appears in the Journal of Medical Microbiology.

“It is possible that this strain of leprosy was proliferated in the South East of England by contact with highly-prized squirrel pelt and meat which was traded by the Vikings at the time this woman was alive,” lead author of the study Sarah Inskip of St. John's College, Cambridge, says in the release. “Strong trade connections with Denmark and Sweden were in full flow in the medieval period, with Kings Lynn and Yarmouth becoming significant ports for fur imports.”

It wasn’t until last year that researchers announced that red squirrels could harbor leprosy. According to Ed Yong at The Atlantic, in the study of 110 squirrels from Britain and Ireland, one-third had the disease. Some even carried the medieval strains of leprosy, which researchers thought had died off centuries before. Until leprosy was detected in squirrels, researchers believed the disease only infected humans and nine-banded armadillos, which spread three cases of the disease to humans in Florida in 2015. (To be fair, humans gave the disease to the armadillos 400 or 500 years ago, so it’s not completely their fault.)

Yet while the idea that the disease came to England from Viking squirrels is intriguing, Inskip says there’s no solid evidence that the pathogen was transmitted from squirrels to humans. There have been no confirmed cases of the disease in the United Kingdom in 200 years, despite the squirrels harboring the bacteria. Inskip says squirrels may be the vector, or it may simply be centuries of contact between East Anglia and Scandinavia that brought the disease to the island.

Given that, there’s no need to stigmatize today's red squirrels because of leprosy. In fact, red squirrels in the British Isles need some extra love. The explosion of invasive North American gray squirrels along with an outbreak of parapoxvirus has pushed the red squirrel to the brink of extinction in Great Britain. Even Prince Charles is committed to restoring the squirrel to its rightful place as lord rodent of the British Isles.     

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