The Transmission of Trypanosoma lewisi by Fleas and Lice

The first experiments upon the transmission of T. lewisi by fleas were carried out by Rabinowitsch and Kempner (1899) who observed that three fresh rats placed with others harbouring trypanosomes in their blood subsequently (after 11–15 days) became infected. Fleas (species?) were found on these rats. They next teazed the bodies of fleas taken from infected rats and inoculated them into fresh rats with the result that in five out of nine experiments the fresh rats became infected with T. lewisi. In one experiment they removed 20 fleas from infected rats and placed them on a clean animal with the result that the latter became infected after 2–3 weeks. They regarded this one experiment as conclusively proving that T. lewisi is transmitted by rat fleas.