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Class Monogenea and Class Cestoda
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2015
Eric S. Loker, Bruce V. Hofkin
The Cestoda, or tapeworms, are divided into two minor groups, the Amphilinidea and Gyrocotylidea, and a major lineage, the Eucestoda. All are endoparasitic, with complex life cycles usually involving two hosts: usually an arthropod in which larval development occurs and a vertebrate definitive host in which the hermaphroditic adult worm is found. Cestodes lack a mouth and gut in all life-cycle stages. Tapeworms have a syncytial tegument featuring microtriches, which are tubelike microvilli that have an electron dense cap. The increased surface area of the tapeworm tegument facilitates uptake of nutrients.
Recent trends in praziquantel nanoformulations for helminthiasis treatment
Published in Expert Opinion on Drug Delivery, 2022
Ana C. Mengarda, Bruno Iles, João Paulo F. Longo, Josué de Moraes
Anthelmintic properties have also been described when PZQ is combined with chitosan, a polysaccharide molecule derived from chitin that possesses biodegradable and biocompatible properties. PZQ-loaded chitosan showed in vitro and in vivo antiparasitic properties against the cestode Echinococcus granulosus [42] and in vivo against trematode S. mansoni [43]. An in vitro test using E. granulosus microcyst presented antiparasitic activity when tested at a concentration of 5 and 10 μg/ml. In addition, microscopy pictures revealed ultra-structural alterations in microcysts with loss of microtriches and cell wall destruction as well as laminated and germinal layer detachments. In vivo, there was a significant reduction in the cyst numbers in mice treated with PZQ-chitosan nanoparticles at 25 mg/kg/daily for 21 days post-infection [42]. In studies using S. mansoni-infected mice, PZQ-chitosan nanoparticles exhibited potent antischistosomal properties at a dose of 250 mg/kg for two successive days, with a worm burden reduction of 86–93%. Significant reductions in the number of eggs and granulomas in the hepatic tissue were also observed in worms exposed to PZQ-chitosan nanoparticles. In addition, PZQ-chitosan nanoparticles caused morphological alterations in the parasite’s tegument, particularly sloughing, erosion of the surface, and numerous blebs emerging from the ventral sucker [43].
Chemical composition and broad-spectrum anthelmintic activity of a cultivar of toothache plant, Acmella oleracea, from Mizoram, India
Published in Pharmaceutical Biology, 2020
Pawi Bawitlung Lalthanpuii, Kholhring Lalchhandama
Scanning electron microscopy revealed that untreated T. tetragona has globular anterior end called sucker, which contains two types of attachment organs, namely rostellum and suckers as shown in Figure 2. The main body (strobila) is composed of a series of body segments called proglottids. The body surface called tegument is smooth because of numerous hair-like microtriches (Figure 3). Remarkable structural changes were seen on T. tetragona after treatment with 20 mg/mL of A. oleracea hexane extract as shown in Figures 4–6. In Figure 4, the scolex appears as massively distorted. The general body surface called tegument is severely shrunken and wrinkled. A sucker is focussed in Figure 5 showing irregularly oriented spines, the parasitic holdfast devices. Some of the spines are clumped and some are detached. Spines are totally removed at the lower area. The body segments (proglottids) are extensively shrunk and folded. There are no signs of hair-like projections called microtriches indicating complete surface erosion (Figure 6).