Two species of bacteria that cause leprosy have been found in red squirrels in Britain and Ireland — a surprising discovery because only primates and armadillos were thought to get the disease.
Stewart Cole at the Swiss Federal Institute of Technology in Lausanne, Anna Meredith at the University of Edinburgh, UK, and their team analysed tissue samples from 110 dead red squirrels (Sciurus vulgaris). Thirteen showed characteristic signs of infection such as skin lesions and swelling of the snout. The authors found leprosy-causing bacteria — Mycobacterium leprae or Mycobacterium lepromatosis — in all visibly ill animals (squirrel with leprosy on ear and snout pictured) and in about one-fifth of symptom-free ones.
This could represent another threat to red squirrels in the United Kingdom and Ireland, which are already affected by other infections and by competition from grey squirrels introduced from North America.