AN APPROACH TO THE DEVELOPMENT OF NEW DRUGS FOR AFRICAN TRYPANOSOMIASIS

African sleeping sickness is caused by Trypanosoma brucei gambiense and T. b. rhodesiense. This disease resulted in the deaths of several million people during the first half of the twentieth century (1) and continues to pose a threat of new epidemics (2). Of even more significance is the fact that animal trypanosomiasis or nagana (T. congolense, T. b. brucei, and T. vivax) makes four million square miles of the African continent unsuitable for the production of cattle and other livestock (3). The first trypanocidal agents were developed by Ehrlich and his collaborators in the early part of this century. Over the next 50 yr, drugs such as tryparsarnide, suramin, pentamidine, berenil, ethidium, Antrycide, and melarsoprol became available for use in the treatment of both sleeping sickness and nagana (4). For the past 20 yr, however, there have been no new chemotherapeutic agents introduced. Moreover, the therapeutic usefulness of the older drugs is diminishing due to the increased incidence of resistant strains (5). We have been attempting to develop new chemotherapeutic agents by