APOL1 and infection: This led to the hypothesis that as T. b. gambiense is found only in West Africa, another variant of APOL1 may exist in some West African primates that is able to kill T. b. gambiense. In this study we examined the serum and APOL1 protein of a West African baboon species, Papio papio, suggested to be refractory to T. b. gambiense infection, with the ability to eliminate parasites in a laboratory infection [64].