Academic literature on the topic 'Acanthocolpidae'

Traditionally, the family Campulidae has been associated either with the family Fasciolidae, parasites of ruminants, or the Acanthocolpidae, parasites of fishes, based on morphological similarities. Since morphology does not seem to resolve clearly the problem of the relationships of campulids, we have used the sequences of the 18S rRNA gene of the campulids Zalophotrema hepaticum, Campula oblonga and Nasitrema globicephalae, the fasciolid Fasciola hepatica, the acanthocolpid Stephanostomum baccatum and the outgroup Schistosoma mansoni to infer a phylogeny. Maximum parsimony and neighbour-joining methods were applied. Both methods indicated that campulids are closer to acanthocolpids than fasciolids. In order to confirm this relationship, we generated a second phylogeny using all the partial sequences of the 18S published for trematodes: Lobatostoma manteri, Echinostoma caproni, Calicophoron calicophorum, Tetracerasta blepta, Gyliauchen sp. and Opistorchis viverrini, plus those mentioned above, and Dicrocoelium dendriticum. The aspidogastrean L. manteri was used as the outgroup. Results were identical to the first analysis. According to this and the most recent Digenean phylogeny, which considers campulids and acanthocolpids as sister groups, we suggest that a common origin for these 2 groups would imply a host-switching process. The life-cycle of acanthocolpids includes marine gastropods as first intermediate hosts, and fishes as second intermediate and definitive hosts. In this context, the hypothesis would be that trematodes whose cycle ended in fishes were able to switch to mammalian hosts.

Cercariae capricornia I–VI, six new cercariae putatively identified as belonging to the Acanthocolpidae, are described and named from prosobranch gastropods of the family Nassariidae collected from the intertidal zone in the Capricornia region, Central Queensland, Australia. Four species are reported from Nassarius olivaceus and two from N. dorsatus. The cercariae have a unique and complex three-dimensional body shape, including a keel, which differentiates them from previously described acanthocolpid cercariae. These are the first cercariae to be described from these gastropods.

Two new Stephanostomum-like cercariae, Cercaria capricornia VII and Cercaria capricornia VIII (Digenea: Acanthocolpidae), are described from the nassariid gastropods Nassarius dorsatus and Nassarius olivaceus collected from the intertidal zone in the Capricornia region of Central Queensland, Australia. Morphological analysis of these new cercariae was augmented with DNA sequence data from the large subunit (LSU) ribosomal DNA region to aid in identification. Bayesian inference analysis of the LSU rDNA revealed that these putative acanthocolpid cercariae nested well within a clade containing species of Stephanostomum, which along with morphological data, suggests they are species of Stephanostomum. Comparative analysis of LSU rDNA sequences also indicates that these two cercariae are not S. adlardi, S. bicoronatum, S. tantabiddii or S. cf. uku, all species known from Australian fishes. The secondary structure of the internal transcribed spacer 2 (ITS2) rDNA region was inferred for these two cercariae using minimum free energy modelling algorithms. Both cercarial types displayed a four helix ITS2 secondary structure model and differed from each other by two compensatory base changes (CBCs) and nine hemi-CBCs.

SummaryThe aim of this investigation was to identify the parasites present in the largely understudied pleasure oyster Crassostrea corteziensis in Sinaloa state in the northwestern Mexican Pacific coast. Inspection of twenty-eight oysters collected on “Ceuta” lagoon revealed the presence of the digenean Stephanostomum sp. (Digenea: Acanthocolpidae) cysts. Metacercariae were found encapsulated and embedded in the digestive gland and mantle tissue of oysters. The prevalence of infection revealed that 84.6 % were infected, the abundance was 13.62, with a mean intensity of 16.09 per host. The members of this genus are characterized by a double crown of spines in the cephalic region surrounding the buccal opening of the worm. Significantly, we report the first incidence of the digenean Stephanostomum sp of the family Acanthocolpidae parasitizing Crassostrea corteziensis. Further we report that this bivalve is now considered a new intermediate host, and the northwestern Mexican Pacific coast is a new geographical distribution area for this digenean. The findings contribute to our understanding of the biology, biodiversity and host preference of these parasites, with implications for health risks posed by human consumption of the pleasure oyster.

Se describe una nueva especie de trematodo del género Pseudacaenodera (Acanthocolpidae). La nueva especie es un parásito de los peces marinos Lutjanus synagris, y se diferencia de las otras dos especies del género Pseudacaenodera, P. Cristata Yamaguti 1965 y P. Karachiense Bilqees & Malik 1980, por su tamaño largo y las numerosas proyecciones cuticulares discoidales (entre 38 y 56), las cuales empiezan en la ventosa oral y alcanzan hasta la mitad del acetábulo, la división del esófago en los dos ciegos intestinales en el nivel anterior al acetábulo, el hospedador final Lutjanus synagris y el tamaño de los huevos. La especie fue colectada en un estudio de trematodo en peces marinos (Lutjanidae) en el Caribe colombiano, Santa Marta. En este trabajo se examinaron 460 peces de seis especies y se encontraron siete familias diferentes y 14 especies de tremátodos digéneos.

"The biodiversity and ecology of marine cercariae in Australia is poorly known. Although nassariid gastropods are widely distributed in Australia and are expected to have a diverse parasite fauna similar to that of other nassariids worldwide, their cercariae have not been characterised. Nassarius dorsatus, N. olivaceus and N. pullus were collected at three separate estuarine localities in central Queensland between August 2004 and August 2006 and their emergent cercariae characterised using morphological and molecular methods. Fifteen morphotypes of cercariae from six families that infect fishes and birds as definitive hosts were characterised. The highest richness was within the Acanthocolpidae (nine morphotypes) which comprised three cercariae interpreted as species of Stephanostomum and a complex of six unusual cercariae with a ventral keel. Molecular characterisation of these six cercariae supported their placement in the Acanthocolpidae and indicated that they comprised only three species, two of which displayed marked phenotypic plasticity. Molecular analysis supported the characterisation of the three species of Stephanostomum and suggested that one of the unusual cercariae was a species of Stephanostomoides. Dissection of fish from Sandy Point provided a single match; the sequence for a metacercaria in Valamugil buchanani, the blue-tail mullet, was identical to that of one of the species of Stephanostomum. There were two cercariae from the Echinostomatidae and one from each of the Lepocreadiidae, Microphallidae, Opecoelidae and Zoogonidae. Molecular analyses supported the placement of the cercariae from the Echinostomatidae, Lepocreadiidae, Opecoelidae and Zoogonidae within their respective families. The cercaria from the Lepocreadiidae was identified by comparison to known adult data and putatively corresponds to Prodistomum keyam, a parasite of Monodactylus argenteus, the silver moony or butter bream, common in the study region. Morphological analysis supported the characterisation of both of the Echinostomatidae as species of Himasthla. Although no other cercariae could be characterised to genus level, the opecoelid cercaria was determined to be in the subfamily Opecoelinae. Nassarius olivaceus was infected by three acanthocolpid cercariae and one cercaria from each of the other families. Nassarius dorsatus was infected by five acanthocolpid cercariae and one each from the Echinostomatidae and Lepocreadiidae. Nassarius pullus was infected by a single cercaria from the Echinostomatidae. Most cercariae were specific to a single species of gastropod; only four infected two species and none infected all three. Cercariae that infect fish as a definitive host were found at all three localities; but cercariae that infect birds were restricted to a single locality, Sandy Point at Corio Bay, important for domestic and migratory bird species. These results emphasise the relative significance of Sandy Point as an important bird habitat. In total, 126 infections were diagnosed (115 by cercarial emergence), with both the highest frequency of infection and number of infections in N. olivaceus (frequency 5.3%; n=102; 81% of infections), followed by N. dorsatus (1.1%; 20; 16%) and N. pullus (0.2%; 4; 3%). The highest number of infections occurred at Sandy Point (66; 52% of infections), followed by Cawarral Creek (38; 30%) and then Ross Creek (22; 17%). The highest number of infections was by the Acanthocolpidae (54; 43%). Diagnosis of infection by emergence was suitable for all cercariae except the opecoelid, which was underdiagnosed. Nassarius olivaceus had the longest survival in captivity (~4.5 y), followed by N. dorsatus (~0.8 y) and N. pullus (~0.3 y). Almost all infections remained patent for the life of the gastropod. Families commonly found in nassariids worldwide include Acanthocolpidae, Echinostomatidae, Lepocreadiidae and Zoogonidae. Nassariid gastropods are also the dominant marine first intermediate hosts for the Acanthocolpidae, Lepocreadiidae and Zoogonidae and one of the three most common first intermediate host families for species of marine Himasthla. Molecular relationships also indicate that the Acanthocolpidae and Brachycladiidae may actually be comprised of three discrete groups, the Stephanostomum + Monostephanostomum group, the Brachycladiidae, and a group of non-Stephanostomum species comprising Pleorchis, Tormopsolus and Stephanostomoides. This research adds information about the parasite assemblages of nassariid gastropods in Australia, adding 12 new cercarial species and 16 new host-parasite records. Cercarial reports for the Acanthocolpidae, Echinostomatidae, Lepocreadiidae, Opecoelidae and Zoogonidae have been comprehensively reviewed and patterns of association between nassariids and their common parasite families presented. As well, this research has provided a potential avenue for a review of the Acanthocolpidae, a family which is currently considered a ‘catch-all’ group."