Immunization of mice with Trypanosoma rhodesiense exposed to ultraviolet irradiation.

Exposure time of Trypanosoma rhodesiense as short as 1 minute to ultraviolet (U.V.) light prevents the organisms from causing infection. Live trypanosome challenge of mice immunized with U.V.-irradiated trypanosomes results in sterile immunity. This allows a method for the induction of protective immunity to experimental trypanosomiasis which can be performed in most laboratories using U.V. germicidal lamps found in sterile hoods.