Regulation of Leishmania populations within the host. IV. Parasite and host cell kinetics studied by radioisotope labelling.

Tritiated thymidine pulse labelling followed by autoradiography has been used to analyse the kinetics of Leishmania donovani infections within the mouse host. Resistant strains of mice show much lower parasite proliferation rates than do susceptible strains. In chronic infections the rate is also reduced. Parasitised mononuclear phagocytes may undergo mitosis. No evidence for selective destruction of parasitised cells in chronic infections was found by labelling methods. It is possible to get parasite labelling in vitro immediately after biopsy to levels comparable to those seen in vivo.