Atovaquone is a competitive inhibitor of ubiquinol, specifically inhibiting the mitochondrial electron transport chain at the bc1 complex.31 Inhibition of bc1 activity results in a loss of mitochondrial function.32,33 During the intra-erythrocytic stage of infection, a key role of the parasite mitochondrion is to provide orotate for pyrimidine biosynthesis through the activity of dihydroorotate dehydrogenase (DHODH). The gene discussed is DHODH; the disease is infection.