Leprosy, also known as Hansen’s disease, is caused by the bacterium Mycobacterium leprae. These Gram-positive, rod-shaped bacteria depend greatly on their host for survival - they have lost many important metabolic genes through the process of “reductive evolution”. Because of this, they are only able to grow inside host cells. Interestingly, humans and armadillos are the only known, definitive hosts for M. leprae.
Leprosy can be treated with a combination of antibiotics and corticosteroids. Drug-resistant strains of bacteria are popping up, so many researchers are working to develop a vaccine. The BCG vaccine for tuberculosis (caused by Mycobacterium tuberculosis, a close relative of M. leprae) has been used with some success to prevent leprosy in both India and Brazil. However, the American Leprosy Missions and the Infectious Disease Research Institute (IDRI) have teamed up to develop a vaccine that consists of four key proteins, and it is currently in clinical trials. The IDRI has also developed a flash-drive-sized diagnostic test for leprosy. If the vaccine is successful, the researchers hope to use the diagnostic test to pinpoint populations most in need of vaccination.
Posted by Dr. Tim Sandle