Leprosy usually evokes images of deformed faces and hands and leper colonies. This disease, caused by Mycobacterium leprae, has been recognized for at least 4000 years, and is thought to have been one of the biblical plagues. While now treatable with proper access to healthcare, leprosy is still a problem in some regions.

Feline leprosy is a disease that is present in cats in certain areas of the world, especially British Columbia Canada, northern New Zealand and eastern Australia. It typically causes granulomas (firm fleshy, tumour-like masses) in the skin and tissues directly under the skin, These can become ulcerated and secondary bacterial infections can develop. Feline leprosy has some similarities to human leprosy, however it’s not the same thing. It is caused by a related but distinct bacterium Mycobacterium lepraemurium. (It’s also suspected that one or more other related bacteria can also cause this disease.) Mycobacterium lepraemurium also causes disease in rodents and can survive in the environment. Cats most likely become infected after being bitten by infected rodents. While the name may be concerning and the disease can be serious in cats, fortunately there is no risk to humans. There is no evidence that this uncommon disease in cats can be transmitted to people.

Image: A photomicrograph of Mycobacterium leprae taken from a leprosy skin lesion. (source: CDC Public Health Image Library ID#2123).