The effect of the immunomodulatory fungal metabolite cyclosporin A (CyA) on the course of Paragonimus miyazakii infection in rats was studied. Administration of CyA 15 to 19 days post-infection resulted in a significantly lower recovery rate of worms and cyst formation in the host's lungs than in controls. Administration of CyA − 1 to + 3 days post-infection enhanced the growth and maturation of P. miyazakii, expressed as weight of worms and the number of worms with eggs in uteri with respect to control values. This study shows that administration of CyA to rats affects the host-parasite relationship, depending on the time of administration of the drug.

Since Fasciola sp. contained proteolytic enzyme(s), it was confirmed that degradation took place in protein components in extracts of the liver flukes, which resulted in lack of clarity of sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Degradation was shown to occur mostly during a heating process of the extract samples. The proteolytic activity in the extracts was completely blocked and electrophoretic patterns were improved only by the use of cysteine proteinase inhibitor N-[N-(L-3-trans-carboxyoxiran-2-carbonyl)-L-leucyl]-agmatine (E-64). Great improvement was also noted in electrophoretic patterns of the extracts of other trematodes, such as Paragonimus westermani, P. miyazakii and Clonorchis sinensis, when their extracts were treated with E-64.