Transmission of leprosy in nude mice through thorn pricks.

The dorsum of the feet of 10 nude mice was smeared with 10(7) Mycobacterium leprae and then pricked with cactus thorns contaminated with M. leprae. In 15 months five of them developed lepromatous nodules at the infected site and disseminated lesions in the ears, nose, tail and the organs of the reticuloendothelial system. Penetrating injuries through unprotected skin contaminated with M. leprae from the environment may play a role in the transmission of leprosy in humans.