However, the main drug used to treat diabetes patients included in this study (metformin) was recently shown to have an in vitro parasite-killing activity against T. cruzi thought to be mediated by the blocking of the mitochondrial respiratory-chain complex I.39In fact, biguanides were first developed to be used as an antimalarial drug, but their effect on lowering blood glucose levels resulted in their use as a drug to treat diabetes mellitus.40 The gene discussed is NDUFV1; the disease is diabetes mellitus.