A second sooty mangabey monkey with naturally acquired leprosy: first reported possible monkey-to-monkey transmission.

The existence of naturally acquired leprosy in a second sooty mangabey monkey has been documented. The disease has the clinical and histopathological characteristics of subpolar lepromatous leprosy (LLs), and microbiological studies thus far confirm the etiologic agent as Mycobacterium leprae. This mangabey had been housed in direct contact with the first mangabey in which naturally acquired leprosy was diagnosed in 1979. Clinical symptoms appeared in the second mangabey in 1986, almost 7 years after the appearance of skin lesions in the first monkey. It is likely that the second mangabey contracted leprosy from the first mangabey or that both animals contracted the disease by contact with an unknown common third source. This is the only known possible natural transmission of leprosy from monkey to monkey, and suggests that a potential zoonosis exists in wild monkeys that may serve as a reservoir for the disease in areas where human leprosy is endemic.