As indicated in the previous section, the antibody levels in either experimental or natural Fasciola infections were much lower for MF6p/FhHDM-1 protein than for L-cathepsins and, as deduced from experimental infections, the antibody response to the MF6p/FhHDM-1 protein did not precede that obtained against L-cathepsins. Here, CTSL is linked to fascioliasis.