Researchers discover how human body fights off African parasite

Trypanosoma are a nasty class of single-celled parasites that cause serious, even fatal, diseases in human and animals. Two species cause sleeping sickness, a disease that threatens all of sub–Saharan Africa. There’s a catch though: one parasite, Trypanosoma brucei brucei (T. b. brucei), infects animals but seems to spare humans, and scientists haven’t quite understood why.