RESUMO
Species in the genus Gorgoderina Looss, 1902 are parasites of the urinary bladder of amphibians and include around 50 species described globally. Molecular data on species of the genus are scarce, as is the information of their life-cycle patterns. During a survey on the genetic characterization of the frog trematodes in the tropical rain forest of Los Tuxtlas, in the Gulf of Mexico slope of Mexico, specimens of two morphotypes of Gorgoderina were sampled from the Rio Grande leopard frog, Rana berlandieri. One of them represented an undescribed species which is described herein as Gorgoderina rosamondae n. sp., whereas the other one was morphologically very similar to an apparently widely distributed North American species, G. attenuata, which has been previously reported in the same geographical area. Specimens of both morphotypes were sequenced for two nuclear and one mitochondrial genes. Phylogenetic trees corroborated the distinction of the new species, and data on the internal transcribed spacer 2 revealed genetic differences between G. attenuata sequenced from frogs in USA and specimens of Gorgoderina sp. from Los Tuxtlas, indicating the possibility that they also represent an undescribed species. COI sequences showed high genetic divergence values between the new species and Gorgoderina sp. from Los Tuxtlas (8.63-9.99%). Additionally, COI sequences of the larval forms (sporocyst, cercariae and metacercariae) sampled in the same locality from their first and second intermediate hosts (Pisidium sp. and Agriogomphus tumens, respectively) showed conspecificity, and the 3 host life-cycle of the new species was elucidated.
Assuntos
Ranidae , Trematódeos/classificação , Infecções por Trematódeos/veterinária , Animais , Cercárias/anatomia & histologia , Cercárias/classificação , Cercárias/crescimento & desenvolvimento , Cercárias/ultraestrutura , Metacercárias/anatomia & histologia , Metacercárias/classificação , Metacercárias/crescimento & desenvolvimento , Metacercárias/ultraestrutura , México/epidemiologia , Microscopia Eletrônica de Varredura , Oocistos/classificação , Oocistos/citologia , Oocistos/crescimento & desenvolvimento , Oocistos/ultraestrutura , Filogenia , Prevalência , Trematódeos/anatomia & histologia , Trematódeos/crescimento & desenvolvimento , Trematódeos/ultraestrutura , Infecções por Trematódeos/epidemiologia , Infecções por Trematódeos/parasitologiaRESUMO
Diplostomum ardeae Dubois, 1969 has seldom been reported since its description from the great blue heron (Ardea herodias L., 1758) in the USA. Sequences obtained in this study from the barcode region of cytochrome c oxidase 1 (CO1) in diplostomids from black-crowned night heron (Nycticorax nycticorax (L., 1758)) in Puerto Rico matched data from D. ardeae from A. herodias in the type region. We also obtained DNA barcodes from morphologically similar diplostomids from a rufescent tiger heron (Tigrisoma lineatum (Boddaert, 1783)) and from metacercariae from eye lenses of Trachelyopterus galeatus (Linnaeus, 1766) from the Paraná River basin in Argentina and Brazil, respectively. Barcodes matched (97-100% identity) in these South American adult and larval specimens as well as in recently published sequences from metacercariae from 11 other siluriform fishes from the same region. Barcodes from the South American species, which we describe as Diplostomum lunaschiae n. sp., differed from those of D. ardeae by 7.2-9.8%, and the new species differs from D. ardeae in its size, pharynx:oral sucker length ratio, egg:body length ratio, and distribution of vitellaria. As in prior phylogenetic analysis of CO1 sequences, both D. ardeae and D. lunaschiae n. sp. were not associated with Diplostomum. In more character-rich analyses of nuclear rDNA and of mitochondrial genomes, D. ardeae was an early divergent member of clades of species of Diplostomum. Consequently, we continue to consider D. ardeae and D. lunaschiae n. sp. members of Diplostomum, in contrast to recent suggestions that these species may belong to a different genus.
Assuntos
Aves/parasitologia , Estágios do Ciclo de Vida , Filogenia , Trematódeos/classificação , Trematódeos/crescimento & desenvolvimento , Animais , Peixes-Gato/parasitologia , Código de Barras de DNA Taxonômico , DNA Ribossômico/genética , Genoma Mitocondrial/genética , Metacercárias/classificação , Metacercárias/genética , Porto Rico , Trematódeos/anatomia & histologia , Trematódeos/genéticaRESUMO
In the Laboratory of Parasites of Fishes, Crustaceans and Mollusks (CEPAVE), we undertook a parasitological study on three species of fish from the Espinal and Esteros del Iberá ecoregions of Argentina. Clinostomid metacercariae were found parasitizing Characidium rachovii, Crenicichla vittata and Gymnogeophagus balzanii. In this study, we analysed the damage that these parasites inflict on their hosts through the evaluation of histological sections. In addition, Clinostomum metacercariae were identified using morphological characters and DNA barcoding. In the pathological analysis, we observed that muscle tissue was the most affected. The inflammatory response showed vascular congestion areas and infiltration of numerous inflammatory cells, mainly lymphocytes. The molecular and morphological approach supports the presence of three new lineages of clinostomid metacercariae in Argentina. This could lead to the discovery of a high number of lineages or species of Clinostomum from South America.
Assuntos
Código de Barras de DNA Taxonômico , Trematódeos/anatomia & histologia , Trematódeos/classificação , Infecções por Trematódeos/patologia , Infecções por Trematódeos/veterinária , Animais , Argentina , DNA de Helmintos/genética , DNA Espaçador Ribossômico/genética , Doenças dos Peixes/parasitologia , Inflamação/parasitologia , Metacercárias/anatomia & histologia , Metacercárias/classificação , Músculos/parasitologia , Músculos/patologia , FilogeniaRESUMO
Abstract Clarias gariepinus is a fish from North of South Africa and was later introduced in several countries, including Brazil. The present study aimed to describe the first report of Diplostomidae metacercariae in C. gariepinus in Brazil. For this, 30 C. gariepinus were captured in a lake in the city of Campos dos Goytacazes, RJ, Brazil. Fishes were euthanized using freezing and necropsied for collection of parasites. The organs were dissected and analyzed for the presence of parasites that were processed for light and scanning electron microscopy. Trematodes were stained with Semichon's Carmine and Gomori's Trichrome, observed and schematized under a light microscope with image analysis software. A total of 190 trematodes were collected from the gills, suprabranchial organs, heart, stomach, intestinal mesentery, liver and body cavity of the fish. The parasites had a foliaceous body divided by a discrete constriction, without genital primordia, and a holdfast organ present at the posterior region, typical of metacercariae of the family Diplostomidae. It was classified as the 'Diplostomulum' morphotype, based on the morphology of the reserve bladder structure. This is the first report of the metacercariae of Diplostomidae parasitizing C. gariepinus in the Americas. This fish acts as an intermediate or paratenic host of this digenean in Brazil.
Resumo Clarias gariepinus é um peixe do Norte da África do Sul e posteriormente introduzido em diversos países, incluindo o Brasil. O presente estudo teve como objetivo descrever o primeiro relato de metacercárias em C. gariepinus no Brasil. Para tanto, 30 C. gariepinus foram capturados em um lago na cidade de Campos dos Goytacazes, RJ, Brasil. Os peixes foram eutanasiados por congelamento e necropsiados para a coleta de parasitos. Os órgãos foram dissecados e analisados para a presença de parasitos que foram processados para microscopia ótica e electronica de varredura. Os Trematodeos foram corados com carmim de Semichon e tricrômico de Gomori, observados e esquematizados sob microscópio ótico equipado com software de análise de imagens. Um total de 190 trematodeos foram coletados das brânquias, órgãos suprabrânquiais, coração, estômago, mesentério intestinal, fígado e cavidade corporal dos peixes. Os parasitos tinham corpo foliáceo, dividido por uma discrete contrição, sem primórdio genital, e órgão tribocítico presente na região posterior, típico das metacercárias da fámilia Diplostomidae. Foram classificados como do morfotipo 'Diplostomulum', baseado na morfologia da estrutura da bexiga de reserva. Este é o primeiro relato de metacercárias de Diplostomidae parasitando C. gariepinus nas Américas. Este peixe atua como hospedeiro intermediário ou paratênico deste Digenea no Brasil.
Assuntos
Animais , Masculino , Feminino , Trematódeos/isolamento & purificação , Peixes-Gato/parasitologia , Metacercárias/isolamento & purificação , Trematódeos/anatomia & histologia , Trematódeos/classificação , Trematódeos/ultraestrutura , Infecções por Trematódeos/veterinária , Peixes-Gato/classificação , Brasil , Microscopia Eletrônica de Varredura , Metacercárias/anatomia & histologia , Metacercárias/classificação , Metacercárias/ultraestrutura , Doenças dos Peixes/parasitologiaRESUMO
Metacercariae of Clinostomum Leidy, 1856 are frequently encountered in freshwater fish. In 2015, a provisional species of Clinostomum in People's Republic of China (PRC) was distinguished from C. complanatum (Rudolphi, 1819) in Europe based on divergent cytochrome c oxidase I (CO1). However, in subsequent studies in East Asia, the same divergent CO1 genotype was identified as C. complanatum. These matching sequences suggest that either the provisional East Asian species was incorrectly distinguished from C. complanatum in 2015 or that C. complanatum in East Asia was misidentified in later studies. We tested these alternatives by sequencing the mitochondrial genome of C. complanatum in Italy, which was 5.7% divergent from a previously published sequence from Clinostomum in PRC, including differences in 80 of 3390 (2.4%) translated amino acids. Partial CO1 sequences of specimens from PRC and those from Italy, Romania, and Turkey also each formed reciprocally monophyletic clades. Partial CO1 from the East Asian clade varied by mean 3.6% (range 2.4-4.8%) from C. complanatum from Italy, Romania, and Turkey; mean intra-clade CO1 variation was 0.3% (range 0-1.9%). Metacercariae from Europe and East Asia display significant morphometric variation, and data from the literature suggest morphological differences in the genital complex of adults. Although sequences of nuclear rDNA did not differ between isolates from the west and East Asia, taken together, these results lead us to describe a new species of Clinostomum.
Assuntos
Filogenia , Trematódeos/classificação , Animais , Ásia , DNA Ribossômico/genética , Peixes/parasitologia , Água Doce/parasitologia , Genoma Mitocondrial/genética , Metacercárias/anatomia & histologia , Metacercárias/classificação , Metacercárias/genética , Especificidade da Espécie , Trematódeos/anatomia & histologia , Trematódeos/genéticaRESUMO
Clarias gariepinus is a fish from North of South Africa and was later introduced in several countries, including Brazil. The present study aimed to describe the first report of Diplostomidae metacercariae in C. gariepinus in Brazil. For this, 30 C. gariepinus were captured in a lake in the city of Campos dos Goytacazes, RJ, Brazil. Fishes were euthanized using freezing and necropsied for collection of parasites. The organs were dissected and analyzed for the presence of parasites that were processed for light and scanning electron microscopy. Trematodes were stained with Semichon's Carmine and Gomori's Trichrome, observed and schematized under a light microscope with image analysis software. A total of 190 trematodes were collected from the gills, suprabranchial organs, heart, stomach, intestinal mesentery, liver and body cavity of the fish. The parasites had a foliaceous body divided by a discrete constriction, without genital primordia, and a holdfast organ present at the posterior region, typical of metacercariae of the family Diplostomidae. It was classified as the 'Diplostomulum' morphotype, based on the morphology of the reserve bladder structure. This is the first report of the metacercariae of Diplostomidae parasitizing C. gariepinus in the Americas. This fish acts as an intermediate or paratenic host of this digenean in Brazil.
Assuntos
Peixes-Gato/parasitologia , Metacercárias/isolamento & purificação , Trematódeos/isolamento & purificação , Animais , Brasil , Peixes-Gato/classificação , Feminino , Doenças dos Peixes/parasitologia , Masculino , Metacercárias/anatomia & histologia , Metacercárias/classificação , Metacercárias/ultraestrutura , Microscopia Eletrônica de Varredura , Trematódeos/anatomia & histologia , Trematódeos/classificação , Trematódeos/ultraestrutura , Infecções por Trematódeos/veterináriaRESUMO
The Diplostomidae include a large group of flatworms with complex life cycles and are frequently found parasitizing the eyes and central nervous system of freshwater fishes. The morphological identification of the metacercariae at species level is not always possible. Thus, molecular tools have become essential to assist in the parasite species determination. This study was aimed at describing two diplostomid metacercariae found in freshwater fish in São Paulo, Brazil, based on morphological characters and in the genetic characterization of COI sequences. Our results showed that the two recognized taxa (Tylodelphys sp. and Diplostomidae gen. sp.) appear to be different from the species already described in South America. Tylodelphys sp. differs morphologically from Tylodelphys xenopi, T. mashonense, T. jenynsiae, and T. scheuringi. The metacercariae of T. clavata and T. conifera are smaller than Tylodelphys sp., while T. podicipina is larger than the metacercariae described here. The phylogenetic analysis of COI sequences yielded Tylodelphys sp. as the sister species of Tylodelphys sp. 4, a species reported from the brain of the eleotrid Gobiomorus maculatus in Oaxaca, Mexico. The metacercariae identified as Diplostomidae gen. sp. are morphologically different from the known diplostomid metacercariae and did not match with other diplostomid sequences available. Diplostomidae gen. sp. is recovered as the sister species of Diplostomum ardeae. Although the morphological evidence and the COI sequences differentiate the metacercariae found, the absence of adult specimens of both species precludes the specific designation. This is one of the first papers that use an integrative taxonomy approach to describe the species diversity of diplostomid trematodes in Brazil.
Assuntos
Doenças dos Peixes/parasitologia , Metacercárias/classificação , Trematódeos/classificação , Infecções por Trematódeos/veterinária , Animais , Brasil , Peixes/parasitologia , Água Doce , Estágios do Ciclo de Vida , Metacercárias/genética , México , Filogenia , Rios/parasitologia , Trematódeos/genética , Trematódeos/isolamento & purificação , Infecções por Trematódeos/parasitologiaRESUMO
Adults of the genus Austrodiplostomum are parasites in cormorants of the New World, whereas metacercariae are parasites from eye globe and brain of freshwater and brackish water fishes. In this study, specimens of Austrodiplostomum mordax from South America (type-species) were analyzed together with other specimens of Austrodiplostomum spp. collected from several locations across Middle America and North America. Partial DNA sequences of the mitochondrial gene cytochrome c oxidase subunit I ( COI), the internal transcribed spacers ( ITS1, ITS2, and 5.8S gene), and the D2-D3, domains of the large subunit ( LSU) of nuclear ribosomal DNA, were generated for both developmental stages and compared with available sequences of Austrodiplostomum spp. Phylogenetic analyses inferred with each molecular marker using maximum likelihood and Bayesian inference revealed the existence of 4 lineages representing 2 described species, A. mordax and Austrodiplostomum compactum (syn. Austrodiplostomum ostrowskiae) and 2 undescribed species of Austrodiplostomum recognized in previous studies. The COI haplotype network inferred with 172 sequences detected 28 haplotypes divided into 4 clusters, separating each other by 33 and 40 substitutions and with a genetic divergence ranging from 9 to 12%. The largest group included specimens identified as A. compactum plus those identified as A. ostrowskiae, supporting the synonymy of both species. As a result, we conclude that A. compactum is widely distributed across the Americas, in locations of the United States, Mexico, El Salvador, Honduras, Costa Rica, Venezuela, Peru, and Brazil. The other 2 undescribed species of the genus Austrodiplostomum were previously recorded in the United States and now are reported in Mexico. These 2 species cannot be described because adult forms have not been found in their definitive hosts. Finally, the species A. mordax has been found only in some lakes from Argentina, and it was validated in this study through molecular analyses.
Assuntos
Doenças das Aves/parasitologia , Complexo IV da Cadeia de Transporte de Elétrons/genética , Doenças dos Peixes/parasitologia , Genes Mitocondriais/genética , Trematódeos/classificação , Animais , Sequência de Bases , Teorema de Bayes , Aves , Encéfalo/parasitologia , América Central , DNA Intergênico/química , DNA Ribossômico/química , Peixes , Água Doce , Haplótipos , Funções Verossimilhança , Metacercárias/classificação , Metacercárias/genética , América do Norte , Filogenia , RNA Ribossômico 5,8S/genética , Águas Salinas , América do Sul , Trematódeos/genética , Corpo Vítreo/parasitologiaRESUMO
Members of the genus Tylodelphys Diesing, 1850 are endoparasites of fish-eating birds, particularly ciconiids, anhingids, and podicipedids across the globe. Metacercariae of Tylodelphys spp. were collected from the cranial and body cavities of freshwater fishes in central and northern Mexico; adults were recovered from the intestine of two species of freshwater diving birds of the family Podicipedidae, commonly known as grebes, in two locations of central Mexico. Specimens were sequenced for two molecular markers, the internal transcribed spacers (ITS1 and ITS2) plus 5.8S gene of the nuclear ribosomal DNA and of the cytochrome c oxidase subunit 1 from mitochondrial DNA. The genetic divergence among the 25 samples (16 metacercariae and 9 adults) and between the newly sequenced specimens and those deposited in the GenBank were estimated. Maximum likelihood and Bayesian inference analyses inferred with each data set revealed the existence of five genetic lineages. Eight metacercariae analyzed in this study were nested in two divergent lineages previously recognized as Tylodelphys sp. 5 and Tylodelphys sp. 6 (sensu Locke et al., Int J Parasitol, 45:841-855, 2015). Five adult specimens recovered from the intestine of the least grebe (Tachybaptus dominicus Linnaeus, 1766) in Tecocomulco Lake, Hidalgo State, nested in a single clade with other sequences identified previously as Tylodelphys aztecae, expanding its distribution range in other areas of central Mexico. The isolates of the metacercariae found in the cranial cavity of the shortfin silverside, Chirostoma humboldtianum Valenciennes, 1835 from Zacapu Lake in central Mexico formed a monophyletic lineage and were recognized as an undescribed species of Tylodelphys. The lack of adult specimens of this lineage in our samples prevented a formal description. However, the metacercariae collected in the cranial cavity of the silverside, Chirostoma jordani Woolman, 1894 and the adult specimens recovered from the intestine of the western grebe, Aechmophorus occidentalis (Lawrence, 1858) from Cuitzeo Lake formed a monophyletic clade, allowing us to link both stages of the life cycle and to describe this as a new species, Tylodelphys kuerepus n. sp. The new species represents the eighth species of the genus described in the Americas and the fourth in the Nearctic region. We briefly discuss the ecological associations between the metacercariae and their second intermediate hosts in relation to the genetic diversity patterns uncovered in our study.
Assuntos
DNA de Helmintos/genética , DNA Mitocondrial/genética , Variação Genética , Metacercárias/genética , Trematódeos/genética , Infecções por Trematódeos/veterinária , Animais , Teorema de Bayes , DNA Espaçador Ribossômico/genética , Peixes/parasitologia , Lagos/parasitologia , Metacercárias/classificação , Metacercárias/crescimento & desenvolvimento , Metacercárias/isolamento & purificação , México , Filogenia , Trematódeos/classificação , Trematódeos/crescimento & desenvolvimento , Trematódeos/isolamento & purificação , Infecções por Trematódeos/parasitologiaRESUMO
The phylogenetic position of Clinostomum heluans Braun, 1899 within the genus Clinostomum Leidy, 1856 is reported in this study based on sequences of the barcoding region of the mitochondrial cytochrome c oxidase subunit 1 gene ( COX1). Additionally, molecular data are used to link the adult and the metacercariae of the species. The metacercariae of C. heluans were found encysted infecting the cichlid fish Australoheros sp. in Minas Gerais, Brazil, whereas the adults were obtained from the mouth cavity of the Great White Egret, Ardea alba, in Campeche, Mexico. The COX1 sequences obtained for the Mexican clinostomes and the Brazilian metacercaria were almost identical (0.2% molecular divergence), indicating conspecificity. Similar molecular divergence (0.2-0.4%) was found between sequences of C. heluans reported here and Clinostomum sp. 6 previously obtained from a metacercaria recovered from the cichlid Cichlasoma boliviense in Santa Cruz, Bolivia. Both maximum likelihood and Bayesian inference analyses unequivocally showed the conspecificity between C. heluans and Clinostomum sp. 6, which form a monophyletic clade with high nodal support and very low genetic divergence. Moreover, tree topology reveals that C. heluans occupies a basal position with respect to New World species of Clinostomum, although a denser taxon sampling of species within the genus is further required. The metacercaria of C. heluans seems to be specific to cichlid fish because both samples from South America were recovered from species of this fish family, although not closely related.
Assuntos
Doenças das Aves/parasitologia , DNA de Helmintos/química , Doenças dos Peixes/parasitologia , Filogenia , Trematódeos/classificação , Infecções por Trematódeos/veterinária , Animais , Sequência de Bases , Aves , Brasil , Ciclídeos/parasitologia , Código de Barras de DNA Taxonômico/veterinária , DNA de Helmintos/genética , Complexo IV da Cadeia de Transporte de Elétrons/química , Complexo IV da Cadeia de Transporte de Elétrons/genética , Metacercárias/classificação , Metacercárias/genética , México , Mitocôndrias/enzimologia , Mitocôndrias/genética , Trematódeos/genética , Trematódeos/crescimento & desenvolvimento , Infecções por Trematódeos/parasitologiaRESUMO
Members of the genus Uvulifer are distributed worldwide and infect aquatic snails and freshwater fishes as first and second intermediate hosts, respectively, and fish-eating birds (kingfishers) as definitive hosts. Metacercariae of Uvulifer spp. were collected from the fins and skin of 20 species of freshwater fishes in Mexico, Guatemala, Honduras, Nicaragua and Costa Rica, and the adults were recovered from the intestine of kingfishers in four localities of Mexico. The genetic divergence among 76 samples (64 metacercariae and 12 adults) was estimated by sequencing the 28S and 5.8S nuclear genes, as well as the internal transcribed spacers ITS1 and ITS2, and one mitochondrial gene (cox1). Maximum likelihood and Bayesian inference analyses inferred with each dataset showed a high genetic diversity within the genus Uvulifer across Middle America, revealing the existence of four genetic lineages that exhibit some level of host specificity to their second intermediate hosts. The metacercariae of lineage 1 were associated with characids and cyprinids in central and northern Mexico. Metacercariae of lineages 2 and 3 were associated with cichlids distributed widely across Middle America. The lack of adults of these lineages in kingfishers, in lineages 2 and 3, or the fact that just a few adult specimens were recovered, as in lineage 1, prevented a formal description of these species. The metacercariae of lineage 4 were found in poeciliids, across a distribution range comprising Mexico, Guatemala, Honduras and Nicaragua, and the adult was found in the green kingfisher in Mexico. The number of specimens sampled for lineage 4, for both gravid adults and metacercariae, allowed us to describe a new species, Uvulifer spinatus n. sp. We describe the new species herein and we discuss briefly the genetic diversity in Uvulifer spp. and the importance of using DNA sequences to properly characterize parasite diversity.
Assuntos
Peixes/parasitologia , Variação Genética , Metacercárias/classificação , Metacercárias/isolamento & purificação , Trematódeos/classificação , Trematódeos/isolamento & purificação , Nadadeiras de Animais/parasitologia , Animais , América Central , Análise por Conglomerados , DNA de Helmintos/química , DNA de Helmintos/genética , DNA Ribossômico/química , DNA Ribossômico/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Complexo IV da Cadeia de Transporte de Elétrons/genética , Especificidade de Hospedeiro , Metacercárias/anatomia & histologia , Metacercárias/genética , Microscopia , Filogenia , RNA Ribossômico 28S/genética , RNA Ribossômico 5,8S/genética , Análise de Sequência de DNA , Trematódeos/anatomia & histologia , Trematódeos/genéticaRESUMO
A complete morphological description, supported by molecular data, of Clinostomum detruncatum metacercariae is reported in this study. The metacercariae were found infecting Synbranchus marmoratus from the Paraná River, municipality of Guaíra, Paraná State, Brazil. The taenioidean uterus is the main morphological characteristic of this species. Both neighbor-joining (NJ) and maximum likelihood (ML) trees showed 2 clear separate clusters grouping together the species from the Palearctic region (Clinostomum complanatum, Clinostomum cutaneum, Clinostomum phalacrocoracis, Clinostomum philippinense) and those from the Nearctic/Neotropical regions (Clinostomum marginatum, Clinostomum tataxumui, C. detruncatum, Clinostomum sp. 7). The latter clade is divided into 2 subclades grouping species from North America and Mexico (C. marginatum and C. tataxumui), and those from Brazil (C. detruncatum and Clinostomum sp. 7).
Assuntos
Doenças dos Peixes/parasitologia , Smegmamorpha/parasitologia , Trematódeos/classificação , Infecções por Trematódeos/veterinária , Animais , Brasil , DNA de Helmintos/química , DNA de Helmintos/isolamento & purificação , Água Doce , Funções Verossimilhança , Metacercárias/anatomia & histologia , Metacercárias/classificação , Metacercárias/genética , Trematódeos/anatomia & histologia , Trematódeos/genética , Infecções por Trematódeos/parasitologiaRESUMO
Metacercariae of Paragonimus mexicanus were collected in crabs Tehuana guerreroensis (Rathbun, 1933) in the municipality of Putla, Oaxaca, Mexico. Metacercariae were found in 20.8% of the crabs collected, with an average of 1.9 metacercarie per crab. Stained metacercariae showed the specific characteristics of P. mexicanus by morphology and sequencing a fragment of the 28S ribosomal gene obtained by PCR. These findings reveal that T. guerreroensis is an intermediate host for P. mexicanus; this new report is relevant considering the potential risk of transmission in the states of Oaxaca and Guerrero, Mexico.