Scolex attachment

The majority of adult tapeworms have an attachment region, the scolex, from which a series of proglottids develop, giving the animal a segmented appearance proglottids distal to... 

Some species, e.g. E. granulosus, will evaginate their scolex in saline alone, but this process may be slow or only temporary, and such a response would be inadequate to bring about the rapid evagination and subsequent attachment to the mucosa which is required if the larva is to avoid being swept away by the continuous peristaltic movements of the gut. The addition of bile, however, produces almost instant evagination in most... 

An alternative approach to studying the migration phenomenon has been adopted by Hopkins Allen (333). These workers severed the scolex of worms (one-worm infections) on day 14, without disturbing the attached scolex from the mucosa. They found that, within 48-72 h, the scolex had moved back to a position where a young worm of that size would normally be found. They suggested that the position of the scolex is, in part, determined by the position of the strobila, which monitors information about its position from all over its surface, balancing the input of adverse information from its tail and head ends (333). They concluded that the preferred site for H. diminuta was 30-50% down the small intestine. 

Fig. 10.4. Potential development of a protoscolex of Echinococcus granulosus or E. multilocularis in different habitats. 1, In the dog gut, the scolex evaginates, the organism attaches to the mucosa, differentiates in a strobilar direction and develops into an adult tapeworm. 2, In vivo, if a hydatid cyst bursts or leaks (as during a surgical operation) each protoscolex can differentiate in a cystic direction and form a (secondary) hydatid cyst. (After Smyth, 1987b.)...

Human infections caused by worms (helminths) represent one of the most important public health problems in the wodd. Helminths form three main categories or phyla Platyhelminths, flatworms Aschelminthes, roundworms and Nemathelminthes, thomy-headed worms. Platyhelminths consist of Trematoda and Cestoda. Members of the class Trematoda, or flukes (schistosomes), are slender leaf-shaped organisms that possess attachment organs in the form of cupshaped hooks called suckers. Members of the class Cestoidea, or tapeworms, are flat and ribbonlike. These worms have serially repeated sections behind the neck and an attachment organ called the scolex. The Aschelminthes (class Nematoda) are roundworms, which have a basic cylindrical shape with major variations in proportions, size, and structure. The Nemathelminthes (Acanthocephala), or thomy-headed worms, are widely distributed among animals and generally do not involve a human host. 

There are two types of flatworms the flukes, whose appearance can best be described as lanceolate or leaflike, and the tapeworms, which are ribbonlike. The latter consist of repeating egg-containing segments, or proglottids (numbering up to several thousand) linked in a chain called a strobilia and attached to a head or scolex. They have no digestive system. Their nutrients are absorbed directly from the host s intestines they are true parasites. 

Cestoda A class of flatworms (see Piaty-HELMiNTHEs) Comprising the tapeworms -ribbon-like parasites within the gut of vertebrates. Tapeworms are surrounded by partially digested food in the host gut so they are able to absorb nutrients through their whole body surface. The body consists of a scolex (head), bearing suckers and hooks for attachment, and a series of pit otdds, which contain male and female reproductive systems. The life cycle of a tapeworm requires two hosts, the primary host usually being a predator of the secondary host. Taenia solium has humans for its primary host... 

Scolex Head end of a tapeworm, with suckers and sometimes hooks that attach to the intestinal wall. 

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