latus is much more developed in comparison with its congeners this may coincide with the higher invasive potential of D. Kuperman & Davydov also stated that the glandular system of D. However, these two species differ in the morphology and life-cycle strategy of their larval stages (the former remain in the body cavity, while the latter migrate to the musculature), and in preferences for the second intermediate and definitive hosts. Most ultrastructural and immunochemistry/immunofluorescense-based studies of diphyllobothriidean plerocercoids have dealt with the congeneric species, Dibothriocephalus dendriticus (Nitzsch, 1824), while few have investigated D. acetylcholin, peptides, serotonin (5-hydroxytryptamin, 5-HT) and synapsin, whose functions are not sufficiently understood. The functional complexity of the scolex is determined by its rich innervation and by presence of distinct molecules identified as neurotransmitters, e.g. microtriches (for their terminology see Chervy ) and a complex of glandular cells (frontal glands), which release their secretory products of perhaps adhesive nature on the tegument. To ensure the latter, the scolex possesses specialised muscular attachment organs, bothria, tiny projections of tegument, i.e. “carpaccio di persico”, “sashimi” and others) and consequent attachment of the tapeworm in the host intestinal mucosa. The successful infection of definitive host is determined by the consumption of raw or undercooked fish flesh (e.g. The infectious stage is represented by plerocercoids inhabiting the musculature of several freshwater fishes including the European perch ( Perca fluviatilis L.). Although the disease is often asymptomatic or manifests as general symptoms of mild abdominal discomfort, several dozen of clinical cases are annually reported in European countries. Diphyllobothrium latum) is one of the causative agents of diphyllobothriosis with an estimated 20 million human cases worldwide. The tapeworm Dibothriocephalus latus (Linnaeus, 1758) (syn. well-developed glandular system and massive hook-shaped uncinate spinitriches, are thus probably required for plerocercoids inhabiting fish hosts and also for their post-infection attachment in the human intestine. ConclusionsĬonfocal laser scanning microscopy and electron microscopy (SEM and TEM) showed the detailed microanatomy of the nervous system in the scolex of plerocercoids, and also several differences in the larval stages compared with adult D. Non-ciliated sensory receptors were observed between the distal cytoplasm of the tegument and the underlying musculature. latus: (i) uncinate spinitriches (ii) coniform spinitriches and (iii) capilliform filitriches. Three different types of microtriches occurred on the scolex and body surface of plerocercoids of D. A well-developed gland apparatus, found throughout the plerocercoid parenchyma, produced heterogeneous granules with lucent core packed in a dense layer. One type of these fibres was found to be serotoninergic and possessed large subtegumental nerve cell bodies. Two types of nerve fibres run from the body surface toward the nerve plexus located in the parenchyma on each side of bothria. latus plerocercoids, including the ultrastructure of the nerve cells possessing large dense neurosecretory granules. The organisation of the central and peripheral nervous system was captured in D. Immunofluorescence tagging was held on whole mount larvae. Parasites were examined using confocal microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Plerocercoids were isolated from the musculature of European perch ( Perca fluviatilis) caught in Italian alpine lakes. This study was targeted mainly on the scolex (anterior part) of the plerocercoid of this species, which facilitates penetration of the parasite in intermediate paratenic fish hosts, and subsequently its attachment to the intestine of the definitive host. However, the process of parasite establishment in both intermediate and definitive hosts is poorly understood.
Diphyllobothrium latum) is a well-known etiological agent of human diphyllobothriosis, which spreads by the consumption of raw fish flesh infected by plerocercoids (tapeworm’s larval stage). In Europe, the tapeworm Dibothriocephalus latus (syn.
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