Surprise: leprosy among British squirrels

One of the symbolic animals of Britain, the red squirrel (Sciurus vulgaris) is threatened by an invisible enemy, which is contributing to the decline of its species: leprosy.

The same bacteria at the origin of leprosy that also affects the man - now known as Hansen's disease - were found in the DNA of some of these rodents in the British Isles. The discovery published in Science, was conducted by researchers at the University of Edinburgh.

WOUNDS SUSPECT. The scientists were investigating the origin of mysterious lesions appeared on the nose, ears, eyelids and legs of some English squirrels. With this goal have sequenced the DNA and blood samples of 100 dead squirrels in England, Ireland and Scotland.

HERITAGE OF OLD DATE. They found that all 25 samples from the Island of Brownsea in Dorset English, were carriers of the bacterium Mycobacterium leprae, the same old pathogen origin of human leprosy in medieval Europe. Others tested positive to another bacterial strain that can infect humans, Mycobacterium lepromatosis.

FEW RISKS (FOR US). The result is somewhat surprising because the last case of plague contracted in Britain dates back to 1798: for centuries, therefore, the squirrels have hosted the bacteria, without transmitting to humans. If you would bring them back from the Middle Ages, when the contacts with the man were more frequent, and these animals are appreciated the flesh may have contributed to human transmission of the disease (or we could avergliela sent to us).

For the same reason the discovery is not a concern for man: although we can contract leprosy from the animals - has already happened with armadillos in nine bands, the only other animal reserves of the bacterium known - contact between man and squirrels they are so narrow and at risk (although it is best not to touch dead fish).

HIDDEN RESERVES. Rather, it worries that the bacterium is lethal for ordinary squirrels, because gray squirrels (Sciurus griseus), an invasive species that compete with them, it would seem immune. The study also confirms that the reserves of the pathogen, which affects 220,000 people every year, especially in developing countries, may be more common than previously thought.