VACCINATION AGAINST CESTODE PARASITES

Cestodes are tapeworm parasites. Infection in the intermediate, host w ith larval (metacestode) parasites causes medically and economically i mportant diseases known as hydatidosis and cysticercosis. Immunization against experimental infection with metacestode parasites has been hi ghly successful, in marked contrast with the relative ineffectiveness of vaccines against infection with most parasitic organisms. High leve ls of immunity against a challenge infection with taeniid cestode eggs can be stimulated by immunization with extracts of the parasites, par ticularly with extracts of the oncosphere life-cycle stage. This led t o the production of a recombinant antigen vaccine against infection in sheep with the parasite Taenia ovis, the first highly effective, non- living vaccine against a parasitic infection in animals or humans. Thi s paper reviews immunity to the adult and metacestode life-cycle stage s of cestode parasites, development and application of the T. ovis vac cine, and prospects for vaccines against other cestode infections.