with conventional PCR is the mitochondrial Nad4. Blouin et al. [160] amplified this Nad4 in adult H. contortus and H. placei and sequenced them and identified differences in the sequences between these two species, concluding that the mitochondrial Nad4 could be used for identification of H. contortus and H. placei, and thus, the diagnosis of the respective infections [160,161]. The gene discussed is MT-ND4; the disease is infection.