In the footsteps of Albert Calmette: an ecological study of TB, leprosy and potential exposure to wild-type Mycobacterium bovis.

Background: One hundred years ago, Albert Calmette developed an avirulent strain of Mycobacterium bovis, but there is no evidence that his BCG strain was more immunogenic than wild-type M. bovis. Geographic variations in BCG efficacy remain ill-understood.