Fasciola hepatica vaccine: we may not be there yet but we're on the right road

Abstract

Major advances have been made in identifying potential vaccine molecules for the con-trol of fasciolosis in livestock but we have yet to reach the level of efficacy required forcommercialisation. The pathogenesis of fasciolosis is associated with liver damage that isinflicted by migrating and feeding immature flukes as well as host inflammatory immuneresponses to parasite-secreted molecules and tissue damage alarm signals. Immune sup-pression/modulation by the parasites prevents the development of protective immuneresponses as evidenced by the lack of immunity observed in naturally and experimentallyinfected animals. In our opinion, future efforts need to focus on understanding how para-sites invade and penetrate the tissues of their hosts and how they potentiate and controlthe ensuing immune responses, particularly in the first days of infection. Emerging ‘omics’data employed in an unbiased approach are helping us understand liver fluke biology and,in parallel with new immunological data, to identify molecules that are essential to parasitedevelopment and accessible to vaccine-induced immune responses.