The development of acquired immunity to tapeworms and progress towards active immunization, with special reference to Echinococcus spp.

An assessment is made of the present state of knowledge on acquired immune responses developed by the intermediate and definitive hosts to tapeworm infections. From this evaluation, some gaps in knowledge and some of the problems associated with the development of practical immunization techniques are described. The principal conclusion reached is that absolute resistance to the larval stage can be acquired and resistance to a number of cestode species can be artificially induced in a number of hosts. Thus, research directed towards isolation and characterization of the functional antigens may lead to the development of vaccines for use in public health programmes, such as for the control of echinococcosis, as well as for improving the present status of meat hygiene in regions where cysticercosis, for example, exists.