Observations on the direct passage from vertebrate to vertebrate of recently isolated strains of Trypanosoma brucei and Trypanosoma rhodesiense

Kittens were readily infected with T. brucei by feeding on the carcases of rats killed during an infection with this trypanosome. T. rhodesiense was readily conveyed from an infected to a healthy monkey by the direct method by means of “interrupted feeding” by Stomoxys. Five guineapigs with T. rhodesiense in their peripheral blood gave birth to young which were found to be infected. The young of another guineapig, born 3 days after the date of the infection of the mother (by fly bite), did not become infected, although they were suckled by their infected parent until her death. Three guineapigs, infected with T. gambiense for at least 40 days before their parturition, produced healthy young. Attempts to transmit T. brucei from dog to dog by the agency of the common flea, Ctenocephalus canis, and attempts to infect clean oxen with T. congolense by injection of the fæces of bovine lice and engorged ticks that had fed upon infected oxen, all failed.