The spectrum of immunomodulating molecules produced by tapeworms is not yet well understood. The aims of this study, on the tapeworm Diphyllobothrium dendriticum, were: 1) detection and quantification of prostaglandins (PGs) E2 and D2 by high performance liquid chromatography; 2) visualization of PGE2 and PGD2 in specific cells, using methods of immunocytochemistry and confocal laser scanning microscopy; and 3) investigation of the ultrastructure of the cells potentially producing PGE2 and PGD2. The PGE2 immunoreaction (IR) was found in the apical terminals of the frontal glands and sensory organs in the tegument and in small neurons belonging to the main cords and commissures. PGE2-IR partly coincided with α-tubulin-IR. PGD2-IR occurred in the muscle fibers of longitudinal and transverse body muscles and coincided with phalloidin TRITC staining. Both PGE2 and PGD2 were found in the flame cells of the excretory system. Ultrastructural study of the tegument revealed two types of structures that potentially produce PGE2: ciliated and unciliated free nerve endings and frontal gland terminals reinforced with neurotubules. In the main nerve cords, small neurons were identified as potentially exhibiting PGE2-immunoreactivity. In homogenates of the plerocercoids, the measured content of PGE2 and PGD2 was 33.15ngmg-1 and 1.94ngmg-1 of fresh tissue weight, respectively. We found evidence of PGE2 and PGD2 in D. dendriticum parasitizing Coregonus autumnalis (fish) and proved excretion of PGE2 and PGD2 in response to C. autumnalis blood serum. Prostaglandins produced by D. dendriticum probably play a dual role: 1) PGE2 and PGD2 potentially modulate the fish antiparasitic immune response; 2) PGE2 is presumably necessary for proper development and function of the nervous system, and PGD2 can act as an antagonist against mediators causing muscle contraction.

The present study provides the first ultrastructural data of the vitellogenesis in a cestode species of the cyclophyllidean family Paruterinidae, aiming to expand the limited data on the vitellogenesis in cyclophyllidean cestodes and to explore the potential of ultrastructural characters associated with vitellogenesis for phylogenetic and taxonomic studies of this order. The process of vitellocyte formation in Dictyterina cholodkowskii follows the general pattern observed in other tapeworms but exhibits several specific differences in the ultrastructure of vitelline cells. The vitellarium contains vitellocytes at various stages of maturation. The periphery of the vitellarium and the space between maturing vitellocytes are occupied by interstitial cells. Differentiation into mature vitellocytes is characterized by high secretory activity, which involves the development of granular endoplasmic reticulum, Golgi complexes, mitochondria and vitelline globules of various sizes. During vitellogenesis, the progressive fusion of these globules results in the formation of two large membrane-limited vitelline vesicles that eventually fuse into a single large vesicle. Mature vitellocytes are composed of a single vitelline vesicle, a high content of cytoplasmic organelles and have no nucleus. No traces of lipid droplets and glycogen granules are detected in the cytoplasm of mature vitellocytes, which might be related to biological peculiarities of this family, i.e. the release of eggs into environment within the tissues of the paruterine organ, which may serve as a source of nutrients for embryos.

Schistocephalus solidus is a well-established model organism for studying the complex life cycle of cestodes and the mechanisms underlying host-parasite interactions. However, very few large-scale genetic resources for this species are available. We have sequenced and de novo-assembled the transcriptome of S. solidus using tissues from whole worms at three key developmental states - non-infective plerocercoid, infective plerocercoid and adult plerocercoid - to provide a resource for studying the evolution of complex life cycles and, more specifically, how parasites modulate their interactions with their hosts during development.
The de novo transcriptome assembly reconstructed the coding sequence of 10,285 high-confidence unigenes from which 24,765 non-redundant transcripts were derived. 7,920 (77 %) of these unigenes were annotated with a protein name and 7,323 (71 %) were assigned at least one Gene Ontology term. Our raw transcriptome assembly (unfiltered transcripts) covers 92 % of the predicted transcriptome derived from the S. solidus draft genome assembly currently available on WormBase. It also provides new ecological information and orthology relationships to further annotate the current WormBase transcriptome and genome.
This large-scale transcriptomic dataset provides a foundation for studies on how parasitic species with complex life cycles modulate their response to changes in biotic and abiotic conditions experienced inside their various hosts, which is a fundamental objective of parasitology. Furthermore, this resource will help in the validation of the S solidus gene features that have been predicted based on genomic sequence.

An analysis at the Mustapha University Hospital Center of Algiers examined 78 hydatid samples collected between 2005 and 2012 to determine the fertility rate of metacestodes and the viability of protoscolices. The fertility rate of the hydatid cysts in humans was 88.4% and the protoscolex viability rate 74.5%. The fertility and viability rates found here are high, despite the use of scolicides.