Helminth-Cestode: Taenia saginata and Taenia solium

Human taeniasis is caused by infection with the adult stage of the tapeworms Taenia saginata and Taenia solium , whereas human cysticercosis/neurocysticercosis results from infection with the larvae (cysticerci) of the latter species. Both of these parasites are zoonoses because the usual hosts for the cysticerci are cattle and swine respectively, from which humans become infected with the adult tapeworm. It would clearly be preferable to actively seek means of breaking the transmission cycle and preventing infection. Because that is still not the case in many countries, food hygiene issues therefore arise if meat that is infected with viable cysticerci reaches the consumer or if food designed for human consumption is contaminated with eggs of T. solium . The worldwide prevalence of these parasites reflects inadequate socioeconomic conditions and inappropriate animal husbandry practices in the cattle and pig populations. A third, more recently identified taeniid, Taenia asiatica is also found in humans, cattle, and pigs but is restricted to Asia. As with the other two taeniids, humans are the definitive hosts, but in contrast both cattle and pigs can serve as intermediate hosts. Fortunately, humans do not act as intermediate hosts for T. asiatica . There is a continuing awareness in both the scientific community and the United Nations agencies of public health importance of human taeniasis and cysticercosis/neurocysticercosis and of the economic importance of cysticercosis in cattle and pigs. The purpose of this article is to outline the history and biology of T. saginata and T. solium , their current medical/veterinary and economic importance, and to discuss in more detail the prospects for improving control by introducing new methods of treatment or animal management and by adopting a rational approach to the development of diagnostic assays and immunoprophylaxis. Taenia asiatica is considered for comparison, where appropriate.