Cestodes: Tapeworms

Abstract

Tapeworms can be classified into 2 orders—Pseudophyllidea and Cyclophyllidea. The adult worm consists of 3 parts; head (scolex), neck and proglottids (strobila). The eggs of Cyclophyllidea and Pseudophyllidea are different from each other. In Cyclophyllidea, the embryo inside the egg is called the oncosphere (hexacanth embryo). It is spherical and has 3 pairs of hooklets. In Pseudophyllidea, the egg is operculated. Clinical disease can be caused by the adult worm or the larval form. In general, adult worm causes mild disease or are asymptomatic, while the larvae can produce serious illness and complications, particularly when they lodge in the CNS or eyes.