Comparison of two geographic strains of Leishmania donovani by resistance of mice to superinfection.

Groups of mice were injected with Leishmania donovani strains Et (Burma) or IS (Sudan) and the courses of infection were followed. Between days 20 and 30 after infection by treatment with pentostam. Et- and 1S-recovered mice were challenged by intravenous injection of amastigotes of each strain. Although resistance to superinfection was apparent the L. donovani strains could not be differentiated by this method.