A comparative study of the infectivity of T.b. rhodesiense isolates from man to 3 species of small laboratory rodents.

To confirm an earlier observation, that some T.b. rhodesiense isolates from sleeping sickness cases had failed to infect normally susceptible Wistar rats, blood samples, freshly drawn from 21 patently parasitaemic SS patients, were each inoculated simultaneously into 3 Swiss T.O. White mice, 3 young Wistar rats and 3 Mastomys natalensis. With the sole exception of one Mastomys, which failed to become infected, the 21 stocks infected all the inoculated rodents. Levels and durations of parasitaemias were significantly less in Mastomys than in either the Swiss mice or the Wistar rats suggesting that, although very susceptible to T.b. gambiense and thus eminently suitable for the isolation of this parasite sub-species, they are much less so for the isolation of T.b. rhodesiense in Zambia.