Ever-increasing complexities of diamidine and arsenical crossresistance in African trypanosomes

The treatment of both human and veterinary African trypanosomiasis is still, to a large extent, dependent on diamidines and melaminophenyl arsenicals. Sixty years after the introduction of pentamidine, a large effort is being made to develop a new generation of diamidines for the treatment of sleeping sickness. However, given the reports of resistance to both diamidines and melaminophenyl arsenicals from the field, including cross-resistance to both classes in single isolates, researchers should proceed with some caution before introducing new diamidines, and a thorough understanding of the causes of resistance and crossresistance will be essential.