Scolex adult

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... 

Table 2.2. Species of adult cestodes with scolex glands, investigated by Kuperman Davydov (19826).

Pig. 2.6. Three types of secretory mechanisms found in the scolex glands of adult cestodes. (After Kuperman Davydov, 19826.)... 

Fig. 9.5. Scolex of Echinococcus granulosus in the duodenum of the dog tissue fixed rapidly with hot Zenker s fluid. The rostellum is extended into a crypt of Lieberkuhn with the hooks lightly penetrating the epithelium, some cells of which have become flattened and destroyed. The adult worm must therefore be considered to be both a tissue and an intestinal parasite.

Although, in many species, the adult scolex does little damage to the mucosa, some species (e.g. D. latum, H. microstoma, Multiceps sp.) can produce marked pathogenetic effects. Consideration of these is beyond the scope of this book. The literature in this field has been reviewed by Arme et al. (25). 

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.)...

For many years, it was generally held that adult cestodes were non-immunogenic or poorly immunogenic (353). This view appeared to be based on the assumption that the scolex of most cestode species made only a loose, non-penetrative contact with the intestinal mucosa. It was recognised that an exceptional case was that of H. nana, which has a larval tissue phase in the villi of man and mice (Fig. 11.6) (which is strongly immunogenic) as well as an adult stage. 

The concept that the scolex of adult cestodes is generally non-penetrative has been shown not to hold for species such as Echinococcus granulosus and E. multilocularis, where the scolex penetrates the crypts of Lieberkiihn and, occasionally, even the lamina propria (Fig. 9.5) often resulting in a complete breakdown of the mucosal epithelium. These species can be regarded as both tissue and lumenal parasites. That the scolex contact is close is reflected in the fact that anti-Echinococcus antibodies appear in dog sera 14 days post-infection (p.i.) (368). It is likely, however, that in many cestodes the scolex contact is more superficial and breakdown of the mucosa may not occur, especially in those species which undergo diurnal migration - see Chapter 9. 

Hulinska, D. Lavrov, V. I. (1981). Morphology and cytochemistry of the adult tapeworm Multiceps endothoracicus with emphasis on the scolex. Folia Parasitologica, 28 227-34. 

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