ABSTRACT
Paul Ehrlich first recognized drug resistance in parasites when he noted loss of sensitivity of trypanosomes to arsenicals (Ehrlich, 1910). He called this ‘arsenic fastness’. Among the protozoan parasites of humans, the best known example of drug resistance is in the malaria parasite Plasmodium falciparum, although it also occurs with a variety of other protozoa including trypanosomes (Apted, 1980), Leishmania (Berman et al., 1982), amoebae (Pitman and Pitman, 1974) and trichomonads (Meingassner and Thurner, 1979; C
erkasovová et al., 1986). Two foci
of chloroquine-resistant P. falciparum malaria were identified almost simultaneously in the late 1950s in Columbia and Thailand. Subsequently, there has been a rapid spread from these foci to cover much of Asia, Oceania, South America and Africa (Bunnag and Harinasuta, 1986). This sudden development and the realization that drug resistance was an important impediment to control of malaria has led to much research (see Chapters 39, 47 and 50). Current reports suggest drug resistance may also now be developing with P. vivax (Rombo et al., 1987).
