IDO1 and malaria: Previous studies that evaluated the role of the tryptophan degradation pathway in malaria have consistently shown that the activity of IDO1 is deleterious, and that it is associated with the development of disease complications (cerebral malaria, severe disease, hypotension, among others) (Sanni et al., 1998; Hansen et al., 2000; Tetsutani et al., 2007; Wang et al., 2010; Woodberry et al., 2017).