British Red Squirrels Carry Bacteria That Cause Leprosy In Humans

Posted: Nov 13 2016, 10:42am CST | by , Updated: Nov 13 2016, 10:48am CST, in News | Latest Science News

 

British Red Squirrels Carry Bacteria that Cause Leprosy to Humans
A red squirrel with leprosy on its ear. Credit: Dorset Wildlife Trust
 

Strains of leprosy are found in red squirrels in British Isles

Red squirrels in Britain and Ireland are carrying strains of leprosy that could cause disabilities and skin ulcers to humans if they are infected. 

Also known as Hansen’s disease, Leprosy epidemic tormented humans in medieval Europe but the disease almost disappeared from the world at the end of Middle Ages without any specific reason.

When researchers from  École Polytechnique Fédérale de Lausanne (EPFL) and the University of Edinburgh have recently examined red squirrels in British Isles with increasing number of sores and swelling, they found that red squirrels are infected with the same bacteria that caused leprosy in the humans of Medieval Europe. 

“It was completely unexpected to see that centuries after its elimination from humans in the UK M. leprae causes disease in red squirrels," said Stewart Cole from EPFL. "This has never been observed before.”

In the latest study, researchers carried out blood and DNA tests on 110 red squirrels from England, Scotland, and Ireland. Some of squirrels were having visible symptoms of leprosy while others did not. However, examination showed that all red squirrels from England's Brownsea Island were infected with the bacterium Mycobacterium leprae, which is the oldest known strain of leprosy and is closely related to the one found in the DNA of leprosy victims buried in Winchester more than 700 years ago.

No squirrels from Scotland and Ireland were found to have this bacterium. But they were carrying another related bacterium called Mycobacterium lepromatosis which can also inflict leprosy.

“The main message of this is that the number of non-human reservoirs of leprosy might be much higher than previously thought.” Lead researchers Charlotte Avanzi told Live Science.

“This is of particular interest in countries where leprosy is still endemic in human[s], where maybe a part of the new cases numbers could be explained by the presence of an animal reservoir.”

Today, leprosy is under control but sill around 200,000 new cases of infectious disease are reported every year worldwide, most of which occur in developing countries. In the U.S., typically 150 cases of leprosy are reported each year.

The chances of people catching the disease from red squirrels are low but certainly cannot be dismissed altogether.  

“The next logical step after this study is to check the red squirrel population outside the British Isles, and that includes Switzerland,” said Andrej Benjak, one of the authors involved in the study.

“Even if there is leprosy in red squirrels in continental Europe, the risk of transmission to people is generally low because of their limited contact with humans and hunting red squirrels is forbidden in most European countries.”

 

 

 

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Hira Bashir covers daily affairs around the world.

 

 

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