Only a few other ESAGs have been characterized in detail in T. brucei: ESAG8 is a protein of unknown function that has been localized to the nucleus (38, 39), whereas ESAG4 is an adenylate cyclase localized to the flagellum membrane (40), and whose activity has been associated with control of parasitemia (41). The gene discussed is ADCY1; the disease is parasitic infectious disease.