Because TrxR is a strong antioxidant that protects T. vaginalis from oxidative stress, the parasite lacks glutathione or catalase and T. vaginalis thioredoxin reductase (TvTrxR) is very different from human thioredoxin reductase (HsTrxR), TvTrxR has been identified as a target for trichomoniasis chemotherapy [12] and is the target of metronidazole and other nitroimidazole drugs [13]. This evidence concerns the gene PRDX5 and trichomoniasis.