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Despite the importance of fish-borne trematodes of the family Opisthorchiidae as causative agents of human liver fluke disease, studies on these parasites outside Asia are relativally scarce. In South America, human focus of amphimerosis is known in Ecuador since the mid-20th century, and Amphimerus spp. have also been reported in wild and domestic mammals. Nevertheless, the knowledge on the snails that act as the first intermediate host of these potentially zoonotic parasites are scarce. Herein, a new cercaria of the pleurolophocercous morphotype found in the freshwater snail Idiopyrgus souleyetianus from Brazil was subjected to morphological and molecular studies. Multigene phylogenetic analyses based on 28S, 5.8S-ITS-2 and Cox-1 sequences enabled the identification of Amphimerus sp., a species distinct from that reported in humans from Ecuador. This cercariae was morphologically compared with other opisthorchiid cercariae known. The possible occurrence of human amphimerosis in Brazil is discussed.

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The present work aimed to study ecological aspects related to the distribution pattern of medically important and native freshwater mollusks, found in a rural municipality in the state of Minas Gerais, Brazil. Malacological captures were carried out in aquatic environments (lentic and lotic) from 46 locations between October 2018 and September 2019. The collected specimens were subjected to taxonomic identification and evaluation for infection with trematode larvae. Qualitative data were used to analyze the similarity and the odds ratios between the environmental variables. In total, 1125 specimens were sampled, belonging to the following species: Biomphalaria glabrata, B. tenagophila, B. straminea, B. kuhniana, B. cousini, Biomphalaria sp., and Drepanotrema cimex (Planorbidae), Stenophysa marmorata (Physidae), Omalonyx sp. (Succineidae), Pseudosuccinea columella (Lymnaeidae), and Pomacea sp. (Ampullaridae). Echinostome, strigeocercaria, and xiphidiocercaria types of larval trematodes were detected in S. marmorata and D. cimex. Of note was the similarity in the distribution of S. marmorata, a supposedly endangered species, with that of the medically important Biomphalaria species, with the two sharing environments. This complex scenario led us to reflect on and discuss the need for the control of important intermediate hosts, as well as the conservation of endangered species. This relevant issue has not yet been discussed in detail, in Brazil or in other countries that recommend snail control.

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Larval didymozoids (Trematoda: Digenea) were discovered parasitizing the hemocoel of the heteropod Firoloida desmarestia (redia mean intensity = 13) and the chaetognaths Flaccisagitta enflata and Flaccisagitta hexaptera (metacercaria mean intensity = 1) during a 2014-2016 systematic study of parasites of zooplankton collected in the central and southern regions of the Gulf of California, Mexico. Didymozoid infection route during the early life cycle was inferred combining morphological (light microscopy) and molecular (mitochondrial cytochrome c oxidase subunit I gene, cox1) evidence. Didymozoid rediae parasitizing F. desmarestia were observed, just after field collection of the host, containing hundredths of completely developed cystophorous cercariae, releasing them though the birth pore at approximately one cercaria every 12 s. Cercariae lost their tails developing into a 'young metacercaria' in 1 d at 22 °C without need of an intermediate host. Molecular analysis of cox1 showed that rediae found in F. desmarestia belong to two distinct didymozoid species (Didymozoidae sp. 1 and sp. 2). Metacercariae parasitizing chaetognaths were morphologically identified as Didymozoidae type Monilicaecum and cox1 sequences showed that metacercariae of chaetognaths matched with these two Didymozoidae sp. 1, and sp. 2 species found parasitizing F. desmarestia, plus a third distinct Didymozoidae sp. 3. These are the first DNA sequences of cox1 gene from didymozoid larvae for any zooplankton taxonomic group in the world. We concluded that F. desmarestia is the first intermediate host of rediae and cercariae, and the chaetognaths are the second intermediate hosts where non-encysted metacercariae were found. The definitive host is still unknown because cox1 sequences of present study did not genetically match with any available cox1 sequence of adult didymozoid. Our results demonstrate a potential overlap in the distribution of two carnivorous zooplankton taxonomic groups that are intermediate hosts of didymozoids in the pelagic habitat. The didymozoid specimens were not identified to species level because any of the cox1 sequences generated here matched with the sequences of adult didymozoids currently available in GenBank and Bold System databases. This study provides baseline information for the future morphological and molecular understanding of the Didymozoidae larvae that has been previously based on the recognition of the 12 known morphotypes.

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Human cercarial dermatitis (HCD) caused by avian schistosomes is an emerging health issue in different parts of the world. Nevertheless, parasite diversity, life cycle, and involvement in HCD remain poorly known or neglected in South America. Herein, we reported data obtained during a long-term malacological survey carried out in Pampulha Reservoir, an urban eutrophic waterbody from Brazil between 2009 and 2012. An ocellate brevifurcate cercaria emerged from 55 of 16,235 (0.34%) specimens of Biomphalaria straminea. Samples of the cercariae were subjected to morphological, experimental, and molecular study (analysis of partial sequences of nuclear 28S and mitochondrial cox1 genes). The molecular analysis revealed that the larva corresponds to an avian schistosome; however, it does not correspond to any named genus. A close related isolate was previously reported in Biomphalaria sudanica from Kenya (molecular divergences of 0.54% and 9.62% for 28S and cox1, respectively). The morphology of this cercaria was compared with other avian schistosome larvae from Biomphalaria spp. Attempts to infect experimentally ducks (Cairina moschata) and mice revealed cutaneous manifestations after exposure to cercariae, but adult parasites were not obtained in these hosts. Phylogenetic analysis suggests this parasite is a putative new genus and species of avian schistosome. The potential involvement of the larvae herein described in cases of HCD in Brazil cannot be ruled out. Surprisingly, HCD was not reported in the country so far, which can be related to difficulties in its diagnosis in areas of overlap with human schistosomes.

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A checklist of larval digeneans parasitising molluscs from inland waters of Argentina is presented here. Based on the bibliographical survey of 113 scientific articles and nine theses published between 1930 and 2021, 213 digeneans were found, which were distributed within 13 superfamilies and 35 families. The parasites were identified in 102 locations, encompassing eight of the sixteen biogeographical provinces in Argentina. Digeneans were found in 34 mollusc species (31 gastropods and three bivalves) belonging to 17 genera. The available data are presented for each digenean species, and included host information, localities, prevalence values, type of habitat, life cycle information (natural or experimental host), and information on material and genetic sequences deposited in repositories. Only 21.1% of individuals were identified to species level, and 8.5% to genus level. In addition, the genetic sequences of only 10 species (4.7%) were available at GenBank. This survey constitutes the first checklist of parasitic helminths in molluscs from inland waters of Argentina.

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To date, 9 species of Schistosomatidae have been found parasitizing the nasal tissues of mammal and bird hosts in the Eastern Hemisphere, 5 species in Rwanda (Africa), 2 in Australia (Oceania) and 2 in Eurasia. During a parasitological survey of black necked swans, Cygnus melancoryphus, an anatid endemic to South America, schistosome worms in the nasal tissue were found; the first in the Americas. Morphological results based on male worms and in isolated eggs. The worms have a spiny tegument, filiform body with rounded posterior end, two muscular suckers, a robust gynaecophoric channel with thickened cross bands, and around 130 testes. The eggs are elongate with an asymmetrical bulge, with a slender process at one end and a longer curved process at the other. Diagnostic morphological characteristics do not match with any schistosome genus. Part of the mitochondrial cox1 and nuclear DNA 28S partial genes were sequenced and compared to Schistosomatidae in GenBank. The genetic results confirm the distinctiveness of the specimens since they do not group with any described genus or undescribed lineage other than cercariae of "Chilina lineage 1" that emerge from the Patagonian Chilina gibbosa, a freshwater snail endemic to South America. Based on morphological and genetic characterization of these schistosomes, these specimens represent a new genus and species that parasitizes black necked swans as adults in the nasal tissue, and C. gibbosa is the first intermediate host, both hosts being endemic to South America.

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Amphistome species belonging to the genus Catadiscus are poorly studied intestinal trematodes found primarily in Neotropical anurans. Herein, developmental stages of an amphistome species found during herpetological and malacological surveys in a temporary marsh pond from Brazil were subjected to morphological (light and scanning electron microscopy) and molecular analyses. Adult parasites recovered from anurans were identified as Catadiscus marinholutzi. Amphistome cercariae found in the planorbid snails Drepanotrema depressissimum and Drepanotrema lucidum from the same waterbody were used for experimental and molecular studies. Immature parasites, morphologically compatible with members of Catadiscus, were experimentally obtained in laboratory-reared tadpoles. Sequencing of a partial region of 28S rDNA gene of both adult and cercariae revealed 100% similarity between these developmental stages, confirming their conspecificity. Phylogenetic analyses were attempted for the first time to reveal the position of a species of Catadiscus in the superfamily Paramphistomoidea. Catadiscus marinholutzi falls in a virtual polytomy together with other paramphistomoids, which leaves its phylogenetic relationships within the group unclear. Moreover, the high genetic divergence to Diplodiscus spp. (10.06­10.84%) cast doubts on the placement of Catadiscus within Diplodiscidae. Hence the species composition of the Diplodiscidae should be re-evaluated in further studies using a broader spectrum of related taxa.

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Xiphidiocercariae were found in the invasive snail Melanoides tuberculata collected during a malacological survey in Ceará-Mirim, State of Rio Grande do Norte, Northeastern Brazil in November 2018 and submitted to morphological and molecular analyses. The morphology revealed similarities between the larvae here reported for the first time in M. tuberculata from Brazil and other xiphidiocercariae described in thiarid snails from Asia and Africa. Phylogenetic analyses based on 28S and ITS-2 sequences revealed that the larvae correspond to an unidentified species of the family Lecithodendriidae. Aspects related to the morphology and taxonomy of xiphidiocercariae found in M. tuberculata are briefly discussed. It is possible that the parasite here reported is a newly introduced species transmitted by M. tuberculata in the American continent.

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The genus LangeroniaCaballero and Bravo-Hollis, 1949, currently contains 6 species of amphibian trematodes distributed in North and Middle America. The type species of the genus, Langeronia macrocirraCaballero and Bravo-Hollis, 1949, occurs in Mexico and is relatively commonly found as a parasite of leopard frogs. However, information regarding its life cycle is lacking. In this paper, we study the life cycle of L. macrocirra in Laguna Escondida, Los Tuxtlas, Veracruz. Definitive hosts (Rana spp.) as well as potential intermediate hosts (gastropods, bivalves, crustaceans, tadpoles, hemipterans, and odonate naiads) were sampled in the locality and studied to search for the presence of adults and larval stages of the trematode. Specimens were morphologically characterized, and some individuals were sequenced for 1 ribosomal gene (28S rRNA) and 1 mitochondrial gene (COI). DNA sequences of the adults obtained from leopard frogs were matched with those of the larval forms in their intermediate hosts (metacercariae, cercariae, and sporocysts) to demonstrate conspecificity. Further, we conducted a detailed study of the tegument of the body surface with scanning electron microscopy to characterize each of the developmental stages of the life cycle of L. macrocirra.

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The fishborne zoonotic trematode Haplorchis pumilio (Looss, 1896) is here reported for the first time in Brazil based on morphological, experimental and molecular studies. Pleurolophocercous cercariae emerged from the invasive snail Melanoides tuberculata collected in the municipality of Ceará-Mirim, state of Rio Grande do Norte, Northeast region of Brazil, in November 2018, were used for experimental infection of guppies, Poecilia reticulata. Metacercariae were extracted from the caudal musculature of these fishes and were used to infect mice. Adult parasites recovered in the small intestine of the mice were morphologically identified as H. pumilio. Molecular sequences were obtained for the Brazilian and Peruvian isolates of H. pumilio, and were compared with data available in GenBank. Analyses of fragments of the nuclear genes 28S (1219 bp) and ITS-2 (290 bp) revealed 98.48-100% similarity between the South American and Asian isolates of H. pumilio. Moreover, new sequences of the mitochondrial gene cox-1 obtained for the Brazilian (797 bp) and Peruvian (646 pb) isolates were 100% similar to a Mexican isolate of this species and 97.54% similar to an isolate from Thailand. This finding reveals the potential for occurrence of human haplorchiasis in Brazil, especially because of the increasing popularity of raw fish dishes in the country.

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BACKGROUND: Schistosomiasis control in endemic areas depends on several factors, including chemotherapy, snail control and adequate sanitation. In this context, the employment of compounds isolated from plants is an important issue regarding infection and snail control. The aim of this study was therefore to evaluate the effects of curcumin (CUR), a compound isolated from Curcuma longa, against snails and embryos of Biomphalaria glabrata, which is the most important intermediate host of schistosomiasis in the Americas, as well as in cercariae, the infecting larval stage of Schistosoma mansoni. RESULTS: CUR presented high activity against B. glabrata embryos and moderate activity against newborn and adult snails. The lethal concentration (LC50 ) values after being exposed for 24 h and evaluated for 7 days were 6.54 (95% confidence interval (CI) 5.86-7.30) µg mL-1 for the embryos and 42.29 (95% CI 33.82-52.87) µg mL-1 and 87.69 (95% CI 68.82-111.7) µg mL-1 for the newborn and adult snails, respectively. Moreover, CUR inhibited the development of embryos and egg hatching, and decreased the fecundity rates of adult snails. CUR also demonstrated cercaricidal activity with LC50 values lower than 10 µg mL-1 at 1, 3, 6, 9 and 12 h, respectively. CONCLUSION: Our data show that CUR has potential molluscicidal and cercaricidal activities. Moreover, as a nutraceutical compound that is toxic to both invertebrate host and parasite, CUR has the potential to be explored as a safe new agent to combat schistosomiasis. © 2019 Society of Chemical Industry.

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Abstract Urban agriculture is very common in the cities, as Rio de Janeiro and adjacencies, being important as economic activity. However, this practice can create appropriate conditions for establishment and maintenance of life cycle of many parasites. Lymneid snails can act as intermediate hosts of many trematodes species, including those that infect humans and wild and domestic. In the present study, the snail Lymnaea columella was collected from an urban watercress plantations and the morphology of cercariae released by them was analyzed by light and scanning electron microscopy. The specimens were identified as xiphidiocercariae, belonging to the Cercariae Ornatae group, of the order Plagiorchiiformes. Histological examination of the digestive gland of the infected snails revealed the presence of developing sporocysts, with hemocitary infiltration and metaplasia in the epithelial tissue.

Resumo Agricultura urbana é muito comum nas cidades, como Rio de Janeiro e adjacências, sendo uma importante atividade econômica de subsistência. No entanto, esta prática pode criar condições adequadas para o estabelecimento e manutenção do ciclo de vida de muitos parasitos. Os moluscos limneídeos podem atuar como hospedeiros intermédios de muitas espécies de trematódeos, incluindo aqueles que infectam humanos e animais selvagens e domésticos. No presente estudo, o molusco Lymnaea columella foi coletado de plantações urbanas de agrião e a morfologia das cercárias liberadas por eles foi analisada por microscopia eletrônica de varredura leve e de varredura. As larvas foram identificadas como xifidiocercárias, pertencentes ao grupo das Cercariae Ornatae, Ordem Plagiorchiiformes. Análises histológicas da glândula digestiva dos moluscos infectados evidenciaram esporocistos, com formação de granuloma e metaplasia do tecido epitelial.

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Trematodes belonging to the superfamily Diplostomoidea have complex life cycles involving birds, mammals and reptiles as definitive hosts, and gastropods and different groups of invertebrates and vertebrates as intermediate hosts. Molecular studies of these parasites are numerous, but data from larval stages in molluscs remain scarce, particularly in South America. The present study focused mainly on five morphotypes of longifurcate cercariae found in Biomphalaria straminea (Dunker, 1848) from Belo Horizonte, Minas Gerais, Brazil, collected between 2009 and 2017. In each morphotype, nuclear internal transcribed spacer (ITS1-5.8S ITS-2) rDNA and mitochondrial cytochrome c oxidase 1 (COI) genes were sequenced. Laboratory-reared fish, Poecilia reticulata Peters, 1859 or snails, Biomphalaria glabrata (Say, 1818) were exposed to cercariae to obtain metacercariae. The morphology of cercariae, experimentally obtained metacercariae, and phylogenetic analyses led to the identification of three species of Diplostomidae [Austrodiplostomum compactum (Lutz, 1928), Crassiphialinae gen. sp. and Hysteromorpha sp.] and two species of Strigeidae (Cotylurus sp., Apharyngostrigea sp.). Previously published sequences allowed species-level identification for only A. compactum, although provisional identifications were possible in two cases. First, the COI from cercariae of Apharyngostrigea sp. in Brazil matched those of metacercariae from naturally infected Cnesterodon decemmaculatus (Jenyns, 1842) in Argentina; although a positive identification is not possible, the material presents morphological similarities with larval stages previously described for A. simplex. Secondly, Cotylurus sp. resembles C. lutzi. Our analysis of previously published COI sequences suggests that Cotylurus cornutus (Rudolphi, 1808) has a Holarctic distribution. Both the morphology of experimentally obtained metacercariae and COI sequences indicate that Hysteromorpha sp. in Brazil is distinct from congeners in North America [Hysteromorpha corti (Hughes, 1929)] and Europe [Hysteromorpha triloba (Rudolphi, 1819)].

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Urban agriculture is very common in the cities, as Rio de Janeiro and adjacencies, being important as economic activity. However, this practice can create appropriate conditions for establishment and maintenance of life cycle of many parasites. Lymneid snails can act as intermediate hosts of many trematodes species, including those that infect humans and wild and domestic. In the present study, the snail Lymnaea columella was collected from an urban watercress plantations and the morphology of cercariae released by them was analyzed by light and scanning electron microscopy. The specimens were identified as xiphidiocercariae, belonging to the Cercariae Ornatae group, of the order Plagiorchiiformes. Histological examination of the digestive gland of the infected snails revealed the presence of developing sporocysts, with hemocitary infiltration and metaplasia in the epithelial tissue.(AU)

Agricultura urbana é muito comum nas cidades, como Rio de Janeiro e adjacências, sendo uma importante atividade econômica de subsistência. No entanto, esta prática pode criar condições adequadas para o estabelecimento e manutenção do ciclo de vida de muitos parasitos. Os moluscos limneídeos podem atuar como hospedeiros intermédios de muitas espécies de trematódeos, incluindo aqueles que infectam humanos e animais selvagens e domésticos. No presente estudo, o molusco Lymnaea columella foi coletado de plantações urbanas de agrião e a morfologia das cercárias liberadas por eles foi analisada por microscopia eletrônica de varredura leve e de varredura. As larvas foram identificadas como xifidiocercárias, pertencentes ao grupo das Cercariae Ornatae, Ordem Plagiorchiiformes. Análises histológicas da glândula digestiva dos moluscos infectados evidenciaram esporocistos, com formação de granuloma e metaplasia do tecido epitelial.(AU)

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A key factor in the colonization probabilities of parasites is the host's characteristic habitat. Considering that rice fields are simple habitats compared with natural wetlands, we comparatively analyzed the composition of the cercariae communities in Biomphalaria snails in an agricultural and a nonagricultural habitat of Corrientes Province, Argentina. We collected 2998 Biomphalaria snails from November 2011 to May 2012: B. tenagophila, B. occidentalis, B. peregrina, and B. orbignyi in the nonagricultural habitat and B. straminea in the agricultural habitat. Nine cercaria species were found in the nonagricultural habitat and 12 in the agricultural habitat, with overall parasite prevalence of 9.27 and 7.69%, respectively. The overall prevalence and mean species richness of cercariae showed no significant differences between habitats. The cercariae communities of the 2 habitats showed low similarity (38%), sharing 4 species. The mean species diversity of cercariae was higher in the nonagricultural habitat. Our results suggest that rice fields provide conditions for the hosts and cercariae that are somewhat similar to those of nonagricultural wetlands, although the contrasting characteristics of habitats can influence the presence of different intermediate and definitive hosts and consequently impact parasite diversity.

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Species of the genus Posthodiplostomum are intestinal parasites of piscivorous birds with worldwide distribution. Recent molecular surveys have focused on developmental stages from vertebrate hosts, with few sequences from larvae found in molluscs. Moreover, most published molecular data are from collections in North America, Europe and Asia, and there are no data for South American species. In the present study, cercariae found in the freshwater limpet Gundlachia ticaga from Brazil were used for morphological, experimental and molecular studies. The longifurcate cercariae, Neascus-type metacercariae obtained in experimentally infected guppies (Poecilia reticulata), and an adult parasite recovered from a mouse were morphologically identified as Posthodiplostomum nanum. Sequences of DNA from internal transcribed spacer (ITS) rDNA and cytochrome c oxidase 1 (cox1) from the cercariae and metacercariae were compared with published data, yielding no matches (ITS divergence ≥ 5.5%, cox1 ≥ 13.9%). Phylogenetic analyses of the ITS sequences suggest paraphyly within the genus Posthodiplostomum, or misidentifications of parasites in molecular studies. For example, ITS sequences of Mesoophorodiplostomum pricei and Posthodiplostomum centrarchi or the unnamed species Posthodiplostomum sp. 8 diverge by only 1.1-1.2% and 0.6%, respectively, and all three species fall within a well-supported clade, suggesting that these isolates are congeneric. The phylogenetic tree obtained for cox1 sequences, although not well resolved, reveals that the type species of the genus, Posthodiplostomum cuticola, does not group with any species previously identified as Posthodiplostomum. Overall, the analyses of molecular data here obtained for P. nanum compared with sequences of related species suggest that a review of this group is necessary. Such studies may result in a split of the genus Posthodiplostomum and the transference of some species currently assigned in this genus to other already described genera.

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Abstract Urban agriculture is very common in the cities, as Rio de Janeiro and adjacencies, being important as economic activity. However, this practice can create appropriate conditions for establishment and maintenance of life cycle of many parasites. Lymneid snails can act as intermediate hosts of many trematodes species, including those that infect humans and wild and domestic. In the present study, the snail Lymnaea columella was collected from an urban watercress plantations and the morphology of cercariae released by them was analyzed by light and scanning electron microscopy. The specimens were identified as xiphidiocercariae, belonging to the Cercariae Ornatae group, of the order Plagiorchiiformes. Histological examination of the digestive gland of the infected snails revealed the presence of developing sporocysts, with hemocitary infiltration and metaplasia in the epithelial tissue.

Resumo Agricultura urbana é muito comum nas cidades, como Rio de Janeiro e adjacências, sendo uma importante atividade econômica de subsistência. No entanto, esta prática pode criar condições adequadas para o estabelecimento e manutenção do ciclo de vida de muitos parasitos. Os moluscos limneídeos podem atuar como hospedeiros intermédios de muitas espécies de trematódeos, incluindo aqueles que infectam humanos e animais selvagens e domésticos. No presente estudo, o molusco Lymnaea columella foi coletado de plantações urbanas de agrião e a morfologia das cercárias liberadas por eles foi analisada por microscopia eletrônica de varredura leve e de varredura. As larvas foram identificadas como xifidiocercárias, pertencentes ao grupo das Cercariae Ornatae, Ordem Plagiorchiiformes. Análises histológicas da glândula digestiva dos moluscos infectados evidenciaram esporocistos, com formação de granuloma e metaplasia do tecido epitelial.

RESUMO

New larval avian schistosomes found in planorbid snails from Brazil and USA were used for morphological and molecular studies. Eggs with a distinctive long polar filament were found in ducks infected experimentally with Brazilian cercariae. Similar eggs were reported previously in wild or experimentally infected anatids from Brazil, South Africa, and the Czech Republic. Molecular phylogenetic analyses showed that the North American and European schistosomes are sister taxa, which are both sister to the Brazilian species. However, these clades do not group with any named genus. Molecular data plus egg morphology suggest that these are new putative genera and species of avian schistosomes that can cause human cercarial dermatitis in the Americas, Africa and Europe.

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Abstract Pleurolophocercous cercariae found in the invasive gastropod Melanoides tuberculata (Müller, 1774) collected in a stream of the Vila do Abraão, Ilha Grande, Angra dos Reis, Rio de Janeiro, Brazil were used for experimental infection that enabled the identification of the heterophyid trematode Centrocestus formosanus (Nishigori, 1924). The parasite has been found in the locality since 2007, after two years of the introduction of M. tuberculata. Recently, from a sample of 483 specimens collected in June 2013, 101 (21%) were found infected with parasite. The potential environmental impacts caused by the parasite occurrence could be underestimated in the country, and actions to monitor and control both the parasite and the mollusk are necessary.

Resumo Cercárias do tipo pleurolofocerca encontradas no gastrópode invasor Melanoides tuberculata (Müller, 1774) coletados em um riacho da Vila do Abraão em Ilha Grande, Angra dos Reis, Rio de Janeiro, Brasil foram utilizadas em estudos de infecção experimental que possibilitaram a identificação do trematódeo heterofiídeo Centrocestus formosanus (Nishigori, 1924). O parasito vem sendo encontrado na localidade desde 2007, dois anos após a introdução do molusco. Recentemente, de uma amostra de 483 espécimes coletados em junho de 2013, 101 (21%) apresentavam-se infectados pelo parasito. Os potenciais impactos ambientais ocasionados pela ocorrência deste parasito podem estar sendo subestimados no país, sendo necessárias ações visando o monitoramento e controle tanto do parasito quanto do molusco.

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Pleurolophocercous cercariae found in the invasive gastropod Melanoides tuberculata (Müller, 1774) collected in a stream of the Vila do Abraمo, Ilha Grande, Angra dos Reis, Rio de Janeiro, Brazil were used for experimental infection that enabled the identification of the heterophyid trematode Centrocestus formosanus (Nishigori, 1924). The parasite has been found in the locality since 2007, after two years of the introduction of M. tuberculata. Recently, from a sample of 483 specimens collected in June 2013, 101 (21%) were found infected with parasite. The potential environmental impacts caused by the parasite occurrence could be underestimated in the country, and actions to monitor and control both the parasite and the mollusk are necessary.(AU)

Cercárias do tipo pleurolofocerca encontradas no gastrópode invasor Melanoides tuberculata (Müller, 1774) coletados em um riacho da Vila do Abraão em Ilha Grande, Angra dos Reis, Rio de Janeiro, Brasil foram utilizadas em estudos de infecção experimental que possibilitaram a identificação do trematódeo heterofiídeo Centrocestus formosanus (Nishigori, 1924). O parasito vem sendo encontrado na localidade desde 2007, dois anos após a introdução do molusco. Recentemente, de uma amostra de 483 espécimes coletados em junho de 2013, 101 (21%) apresentavam-se infectados pelo parasito. Os potenciais impactos ambientais ocasionados pela ocorrência deste parasito podem estar sendo subestimados no país, sendo necessárias ações visando o monitoramento e controle tanto do parasito quanto do molusco.(AU)

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