Persistence and distribution of Mycobacterium leprae in Aedes aegypti and Culex fatigans experimentally fed on leprosy patients.

Laboratory reared Aedes aegypti and Culex fatigans were experimentally fed on untreated lepromatous leprosy patients and the proboscides, guts and faeces of the mosquitoes were examiend at 12 hour intervals to determine the persistence and distribution of Mycobacterium leprae. In A. aegypti, bacilli persisted in proboscis till 156 hours, in gut 96 hours, and in faeces 72 hours after feeding. In C. fatigans--proboscides 144 hours, gut 96 hours and faeces 72 hours after feeding. In A. aegypti solid bacilli were present in proboscis upto 96 hours; in gut 48 hours and in faeces 42 hours after feeding. Corresponding figures for C. fatigans were: 144 hours for proboscis, 48 hours for gut, solid bacilli being absent in faeces. The results are discussed from the point of view of arthropod transmission.