Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.


Red squirrels get leprosy

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.

Credit: Catherine Clark

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.

Science 354, 743–746 (2016)

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Red squirrels get leprosy. Nature 539, 333 (2016).

Download citation


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing