Folia Parasitologica最新文献

The sicklefin redhorse, Moxostoma sp. (Cypriniformes: Catostomidae), is an innominate imperiled catostomid endemic to the Hiwassee and Little Tennessee river basins, which has been restricted to a few tributaries of these systems by impoundments. During collections to propagate sicklefin redhorse for reintroduction, a myxozoan, described herein, was observed infecting sicklefin redhorse in the Little Tennessee River Basin, North Carolina. Myxobolus naylori Ksepka et Bullard sp. n. infects the stratum spongiosum covering the scales of sicklefin redhorse. Myxospores of the new species differ from all congeners by the combination of having a mucous envelope, intercapsular process, and sutural markings as well as lacking an iodinophilic vacuole in the sporoplasm. A phylogenetic analysis of the 18S rDNA gene recovered the new species in a polytomy with Myxobolus marumotoi Li et Sato, 2014 and a clade comprised of species of Myxobolus Bütschli, 1882; Thelohanellus Kudo, 1933, and Dicauda Hoffman et Walker, 1973. Histological sections of infected sicklefin redhorse skin revealed myxospores within a plasmodium in the stratum spongiosum dorsal to scales, encapsulated in collagen fibres, and associated with focal erosion of scales directly beneath the plasmodium; in some instances, the scale was perforated by the plasmodium. The specificity of the new species to sicklefin redhorse may make it a useful biological tag to differentiate sicklefin redhorse from morphologically similar species. The new species is the first parasite reported from sicklefin redhorse, a species of concern to the United States Fish and Wildlife Service. No species of Myxobolus has been reported from species of Moxostoma in the Southeast United States. As it was observed that Myxobolus minutus Rosser, Griffin, Quiniou, Alberson, Woodyard, Mischker, Greenway, Wise et Pote, 2016 is a primary junior homonym of Myxobolus minutus Nemeczek, 1911, we propose the replacement name Myxobolus diminutus (Rosser, Griffin, Quiniou, Alberson, Woodyard, Mischker, Greenway, Wise et Pote, 2016).

A total of 52 specimens of the Pacific seabream Acanthopagrus pacificus Iwatsuki, Kume et Yoshino from the Gulf of Tonkin off Vietnam were examined for monogeneans. Twenty fish were parasitised by 101 individuals of five monogenean species, including two known species Allodiscocotyla diacanthi Unnithan, 1962 and Heterapta chorinemi (Tripathi, 1956), as well as three new species, Polylabroides tienyenensis sp. n., Polylabroides tonkinensis sp. n. and Metacamopia lebedevi sp. n. Polylabroides tienyenensis and P. tonkinensis are morphologically more similar to Polylabroides guangdongensis Zhang et Yang, 2001 in comparison with other species within the genus, based on the absence of small spines on the cirrus. However, P. tonkinensis is distinguished from P. guangdongensis by fewer clamps on the haptor and by the different shapes of the large spines on the cirrus. Similarly, P. tienyenensis differs from P. guangdongensis by vaginal ducts with fewer branches, fewer clamps and smaller egg size. Metacamopia lebedevi is distinguished from Metacamopia chorinemi (Yamaguti, 1953) by the arrangement of testes (one row vs two rows), diverticula absent in the oesophagus, and the number of anchor pairs (one vs two); it differs from Metacamopia oligoplites Takemoto, Amato et Luque, 1996 by the smaller haptor, shape and absence of small sclerotised hooks, the number of ribs in their clamps, and the position of the testes; it can be separated from Metacamopia indica (Unnithan, 1962) by having fewer testes and lacking sclerotised structures in the vagina. The present study also provides the measurements for A. diacanthi, H. chorinemi, and proposes a new key to all species of Polylabroides.

The parasite communities of predatory fish can be species rich and diverse, making them effective models for studying the factors influencing temporal and spatial variation in these communities. Over a ten-year period an initial study was done on the metazoan parasite communities of Scomberomorus sierra (Jordan et Starks) from four locations on the south-central Pacific coast of Mexico. Twenty-four metazoan parasite taxa were identified from 674 S. sierra specimens: three species of Monogenea, eight Digenea, one Cestoda, one Acanthocephala, four Nematoda, five Copepoda, and two Isopoda. The parasite communities were characterised by high ectoparasite species richness, with monogeneans and some didymozoid species being numerically dominant. Community structure and species composition varied between locations, seasons and sampling years. Similarity between the component parasite communities was generally low, despite the occurrence of a distinctive set of host-specialist parasites. Interannual or local variations in some biotic and abiotic environmental factors are possible causes of the observed variations in the structure and species composition of the parasite community of S. sierra. Ecological factors were therefore considered to have more influence than phylogenetic aspects (host phylogeny) on parasite community structure.

The elastase, which belongs to the serine protease family, hydrolyses various proteins and may be involved in the parasite invasion. In this study, complete sequence of elastase-1 (TsE) the nematode Trichinella spiralis (Owen, 1835) was cloned into the plasmid pcDNA3.1 as TsE DNA vaccine. After intramuscular vaccination, serum anti-Trichinella antibodies (IgG and subclass IgG1/IgG2a, and IgA), total and specific intestinal mucosal sIgA in mice vaccinated with pcDNA3.1/TsE were measured by ELISA. The results showed that vaccination with pcDNA3.1/TsE induced a systemic humoral immune response (high levels of serum IgG and subclass IgG1/IgG2a and IgA) and local intestinal mucosal immune responses (high levels of TsE-specific sIgA). Vaccination of mice with TsE DNA vaccine also triggered a systemic and local concomitant Th1/Th2 response, as demonstrated by significant elevation of Th1 (IFN-γ and IL-2) / Th2 (IL-4 and IL-10) cytokine levels after the spleen, mesenteric lymph node and Peyer's patch cells from vaccinated mice were stimulated with recombinant TsE (rTsE). The vaccination of mice with pcDNA3.1/TsE displayed a 17% reduction of intestinal adult worms and a 39% reduction of muscle larvae. Our results indicated that TsE DNA vaccine elicited a systemic concomitant Th1/Th2 response and an enteral local sIgA response, and produced a partial protection against infection with T. spiralis. The TsE may be regarded as a potential candidate vaccine target against Trichinella infection. The oral polyvalent vaccines should be developed to improve the protective efficacy of anti-Trichinella vaccines.

We encountered two cases of infection with large female nematodes of the genus Philometra Costa, 1845 in the body cavity of a map puffer Arothron mappa (Lesson) caught off Okinawa, Japan, and a blackspotted puffer Arothron nigropunctatus (Bloch et Schneider) caught off Queensland, Australia, both reared in aquariums in Japan. No morphological difference was observed between the nematodes from A. mappa and A. nigropunctatus. We identified the nematodes as Philometra pellucida (Jägerskiöld, 1893) based on their morphology. The sequences of the nematodes from both hosts were identical to each other (1,643 bp) and formed a clade with other 17 nematodes belonging to the genera Philometra and Philometroides Yamaguti, 1935 with high bootstrap value (bp = 100). It is the first time that the genetic data on P. pellucida are provided. Philometra robusta Moravec, Möller et Heeger, 1992 is synonymised with the former species.

Borrelia burgdorferi sensu lato (s.l.) is the etiological agent of Lyme disease, transmitted by ticks of the genus Ixodes Latreille. Diagnosis of Lyme disease in humans is often difficult and a detailed knowledge of the circulation of B. burgdorferi s.l. in tick hosts is therefore fundamental to support clinical procedures. Here we developed a molecular approach for the detection of B. burgdorferi s.l. in North Italian Ixodes ricinus (Linnaeus). The method is based on the amplification of a fragment of the groEL gene, which encodes a heat-shock protein highly conserved among B. burgdorferi s.l. species. The tool was applied in both qualitative and Real-time PCR approaches testing ticks collected in a North Italian area. The obtained results suggest that this new molecular tool could represent a sensitive and specific method for epidemiological studies aimed at defining the distribution of B. burgdorferi s.l. in I. ricinus and, consequently, the exposure risk for humans.

An infection model for sharpsnout seabream Diplodus puntazzo (Walbaum) challenged with the myxosporean Enteromyxum leei (Diamant, Lom et Dyková, 1994), resembling the natural infection conditions, was used to evaluate the antiparasitic efficacy of a functional diet. Fish of an average weight of 12.5 ± 1.2 g were delivered either a functional (included as feed supplement at 0.3% levels) or a control extruded diet. After four weeks of administration of the experimental diets, fish were challenged with the parasites (cohabitation with infected donors; donor: recipient ratio 1 : 1). The experiment was terminated four weeks after the start of the challenge. At the end of the experiment, growth and feeding (specific growth rate and feed efficiency), as well as immunological parameters (respiratory burst activity, antibacterial activities, hemoglobin concentration, anti-protease activity and ceruloplasmin activity) were measured along with cumulative mortality and total parasitic count in the gut. No significant difference was evident with regard to growth and feeding performance, mortality, gut parasitic load or immunological parameters as the parasitical challenge significantly affected both the performance of the control and functional diet fed fish. However, there was a less prominent impact on antibacterial, anti-protease and ceruloplasmin activity in fish fed with the functional diet. Overall, the present study validated the experimental cohabitation infection model and evaluated the efficacy of a functional ingredient as an antiparasitic agent, showing some potential effects on the fish immune response.

Hexokinase (HXK) is the first key enzyme in the glycolytic pathway and plays an extremely important role in energy metabolism. By searching the microsporidian database, we found a sequence (NBO_27g0008) of Nosema bombycis Nägali, 1857 with high similarity to hexokinase-2, and named it as NbHXK2. The NbHXK2 gene has 894 bp and encodes 297 amino acids with 34.241 kD molecular weight and 5.26 isoelectric point. NbHXK2 contains 31 phosphorylation sites and 4 potential N-glycosylation sites with signal peptides and no transmembrane domain. Multiple sequence alignment showed that NbHXK2 shares more than 40% amino acid identity with that of other microsporidia, and the homology with hexokinase-2 of Nosema tyriae Canning, Curry, Cheney, Lafranchi-Tristem, Kawakami, Hatakeyama, Iwano et Ishihara, 1999, Nosema pyrausta (Paillot, 1927) and Nosema ceranae Fries, Feng, da Silva, Slemenda et Pieniazek, 1996 was 89.17%, 87.82% and 69.86%, respectively. Phylogenetic analysis based on the amino acid sequence of hexokinase showed that all microsporidia cluster together in the same clade, and are far away from animals, plants and fungi, and that N. bombycis is closely related to N. tyriae; N. pyrausta; N. ceranae and Nosema apis Zander, 1909. Immunolocalisation with the prepared polyclonal antibody showed that NbHXK2 was mainly distributed in the cytoplasm and plasmalemma in proliferative, sporulation stage and mature spore of N. bombycis. qRT-PCR assay showed that the NbHXK2 expressed at higher level during spore germination and at early stage of proliferation. These results indicate that N. bombycis may use its own glycolytic pathways to supply energy for infection and development, especially germination and in the early stage of proliferation, and acquire energy from the host through certain ways as well.

Taeniosis-cysticercosis caused by Taenia crassiceps (Zeder, 1800) is a useful experimental model for biomedical research, in substitution of Taenia solium Linnaeus, 1758, studied during decades to develop effective vaccination, novel anti-helminthic drugs and diagnostic tools. Cysticercosis in mouse (Mus musculus Linnaeus) is achieved by the larval subculturing of the Wake Forest University (WFU) strain of T. crassiceps. Golden hamster, Mesocricetus auratus (Waterhouse), has been shown to be the most suitable host for adult forms of parasite in experimental taeniosis. Metacestodes of T. crassiceps WFU multiply by budding without restrictions once inoculated into the mouse, while the number of tapeworms developed from these larvae in hamsters remains highly variable. Three objectives have been proposed to improve the infection of T. crassiceps WFU in hamsters: (1) to re-evaluate the need of immune suppression; (2) to investigate the advantage of infecting hamsters with metacestodes with in vitro protruded scolices; and (3) to compare a number of tapeworms developed from metacestodes subcultured in hamsters against those proliferated in mice. Our results demonstrated that when the evagination of murine metacestodes was high, the number of T. crassiceps WFU adults obtained from hamsters was also high. Immunosuppressive treatment remains relevant for this experimental rodent model. The hamster-to-hamster cysticercosis-taeniosis by T. crassiceps overcame the mouse-to-hamster model in the yield of adult specimens. In vitro scolex evagination and metacestode asexual proliferation in hamsters place this rodent model by T. crassiceps WFU as the most affordable experimental models with taeniids.

A survey of the species of the Proteocephalus-aggregate from sticklebacks (Actinopterygii: Gasterosteidae) is provided. The occurrence of three species in North America is confirmed: (i) Proteocephalus filicollis (Rudolphi, 1802), which has been reported from the three-spined stickleback, Gasterosteus aculeatus Linnaeus, in the northeastern part of North America (Newfoundland); (ii) Proteocephalus pugetensis Hoff et Hoff, 1929 occurs also in G. aculeatus, but in northwestern North America (British Columbia and Washington); and (iii) Proteocephalus culaeae sp. n., which is described from the brook stickleback, Culaea inconstans (Kirtland), in Manitoba (Canada). Another species, Proteocephalus ambiguus (Dujardin, 1845), a specific parasite of the nine-spined stickleback, Pungitius pungitius (Linnaeus), and type species of the genus, has also been found in North America (Alberta, Canada), but its vouchers are in poor condition and cannot be reliable assigned to this species. Both species reported from three-spined stickleback differ from each other by the shape of the scolex (rounded in P. filicollis versus continuously tapered towards the anterior extremity in P. pugetensis) and the apical sucker (widely oval to subspherical in frontal view in P. filicollis versus flattened in P. pugetensis). Proteocephalus culaeae sp. n. is characterised by a short body composed of a few, continuously widened proglottids, a short scolex narrower than the strobila and devoid of an apical sucker, a short, pyriform cirrus sac, no vaginal sphincter, and few testes. A key to species of the Proteocephalus-aggregate from sticklebacks is provided.