Showing papers on "Digenea published in 2022"

A record of two species of Acanthocephala (Echinorhynchida: Rhadinorhynchidae) from Red Sea fishes, Yemeni coastal waters

Abstract: A total of 198 specimens belonging to four fish species (Thunnus tonggol, Sphyraena barracuda, Pomadasys argenteus and Lutjanus gibbus) were purchased from Al-Mehwat fish market, Hodeidah, Yemen and inspected for acanthocephalan infections. Two acanthocephalans were detected. Juveniles of Serrasentis sagittifer were recovered from the intestine, pyloric caeca, body cavity, mesenteries and some internal organs of the above- named fishes with prevalence of 11.7%, 11.9%, 24% and 4.4%, respectively and a mean intensity of 3.3, 2.2, 5 and 2, respectively. Generally, male fishes showed higher values of infection in comparison with female fishes. Encysted juveniles of Gorgorhynchus sp. were recovered from the intestinal mesenteries of T. tonggol only with a prevalence of 3.3% and intensity of 2.5. The occurrence of the above-named acanthocephalans represents their first record from the Yemeni fishes of the Red Sea

Morphological, Behavioral, and Molecular Characterization of Avian Schistosomes (Digenea: Schistosomatidae) in the Native Snail Chilina dombeyana (Chilinidae) from Southern Chile

Abstract: Avian schistosomes are blood flukes parasitizing aquatic birds and snails, which are responsible for a zoonotic disease known as cercarial dermatitis, a hypersensitive reaction associated to the cutaneous penetration of furcocercariae. Despite its worldwide distribution, its knowledge is fragmentary in the Neotropics, with most of data coming from Argentina and Brazil. In Chile, there are only two mentions of these parasites from birds, and one human outbreak was associated to the genus “Trichobilharzia”. However, the identity of such parasites is pending. The aim of this study was to identify the furcocercariae of avian schistosomes from Southern Chile using an integrative approach. Thus, a total of 2283 freshwater snails from different families were collected from three different regions. All snails were stimulated for the shedding of furcocercariae, but only Chilina dombeyana (Chilinidae) from the Biobío region was found to be parasitized. The morphology and phylogenetic analyses of 28S and COI genes stated two lineages, different from Trichobilharzia, shared with Argentina. This study provides new information on Neotropical schistosomes, highlighting the need for major research on these neglected trematodes, which are considered to be emerging/re-emerging parasites in other parts of the globe as consequence of anthropogenic disturbances and climatic change. Highlights: 1. Two different lineages (Lineage I and II) were described and molecularly characterized (28S and COI genes); 2. Cercaria chilinae I y II are proposed as a synonymous of Lineage II. Thus, a total of four different lineages of avian schistosomes are related to Chilina spp.; 3. Chilina spp. represents an important intermediate host for avian schistosomes in South America, constituting a reservoir de schistosomes with zoonotic potential; 4. Coinfection between the two different lineages was found, a finding previously not reported for avian schistosomes; 5. Expansion in the geographic distribution of Nasusbilharzia melancorhypha from its original record in Argentina, with Chilina dombeyana as an additional intermediate host.

Histopathological survey for parasite groups in Gammarus varsoviensis (Amphipoda).

Abstract: Invasive non-native amphipods (Crustacea) are becoming a model system in which to explore the impact and diversity of invasive parasites-parasites that are carried along an invasion route with their hosts. Gammarus varsoviensis is a freshwater amphipod species that has a recently explored invasion history. We provide a histopathological survey for a putatively invasive non-native population of this amphipod, identifying 8 symbiotic groups: Acanthocephala, Rotifera, Digenea, ciliated protozoa, Haplosporidia, Microsporidia, 'Candidatus Aquirickettsiella', and a putative nudivirus, at various prevalence. Our survey indicates that the parasites have no sex bias and that each has the potential to be carried in either sex along an invasion route. We discuss the pathology and prevalence of the above symbiotic groups and whether those that are parasitic may pose a risk if G. varsoviensis were to carry them to novel locations.

Helminth endoparasites of endemic fish Pygocentrus piraya (Characiformes, Serrasalmidae) from Três Marias reservoir, Minas Gerais, Brazil.

Abstract: Ten endoparasite species found in Pygocentrus piraya, which is a piranha species native to São Francisco river, were collected from 108 fish caught in Três Marias reservoir in 2004 and 2005, namely: Digenea - Austrodiplostomum sp. (metacercariae); Eucestoda - Proteocephalidae gen. sp. (plerocercoids); and Nematoda - Procamallanus (Spirocamallanus) inopinatus, Cystidicoloides fischeri and Capillostrongyloides sentinosa (adults); Spinitectus rodolphiheringi (juvenile); Hysterothylacium sp., Contracaecum sp. Type 1, Spiroxys sp. and Goezia sp. (larvae). In helminth fauna, P. (S.) inopinatus has shown higher prevalence and dominance. Fish sex has influenced the prevalence of Hysterothylacium sp., which was higher in female specimens. Longer total length of fish has positively influenced the abundance of C. sentinosa and Hysterothylacium sp.. The rainy season has favored parasitic indices, mainly P. (S.) inopinatus abundance, as well C. sentinosa and Hysterothylacium sp. prevalence and abundance. There were co-occurrences between adult and some larval nematodes. Endemic piranhas, as well as final hosts, are important intermediate and/or paratenic hosts, given the relevant number of larvae (proteocephalideans and nematodes) of heteroxene cycle found in them. Proteocephalidae gen. sp., C. sentinosa, Hysterothylacium sp., Contracaecum sp. Type 1, Goezia sp. and S. rodolphiheringi are new records parasitizing P. piraya in São Francisco basin.

Marine fish parasites of Vietnam: a comprehensive review and updated list of species, hosts, and zoogeographical distribution

Abstract: With a long coastline stretching from tropical to subtropical climate zones, and an immense exclusive economic zone with over 4000 islands, the Vietnamese marine waters support a rich and biodiverse parasite fauna. Although the first parasitological record was in 1898, systematic studies of the parasite fauna have increased during the last 50 years. This comprehensive review covers the current state of knowledge of marine fish parasites in Vietnam and lists 498 species found in 225 fish species, and their geographical distribution. In addition, 251 marine parasite species have newly been added to the already known fauna of 247 species since 2006 (more than two-fold increase). The most speciose group was the Digenea, which accounted for 43% of the total parasite species biodiversity, followed by Monogenea (23.5%), Crustacea (11.6%), Nematoda, and Acanthocephala (8.0% each). The shallow and muddy Gulf of Tonkin showed a rich parasite fauna, accounting for 66.3% of the whole marine parasite fauna of Vietnam, with Digenea accounting for 51% of the regional total parasite richness, followed by Monogenea (27%), Acanthocephala (8.8%), and Nematoda (5.8%). Only a few species belonged to Hirudinea, Myxozoa, and Cestoda, suggesting that these taxa may be understudied. Despite significant progress in studies of marine fish parasites in Vietnam since 2006, only about 12% and 13% of the total fish species have been examined for parasites in the whole country and the Gulf of Tonkin, respectively.

A new species, new host records and life cycle data for lepocreadiids (Digenea) of pomacentrid fishes from the Great Barrier Reef, Australia

Abstract: A new species of lepocreadiid, Opechonoides opisthoporus n. sp., is described infecting 12 pomacentrid fish species from the Great Barrier Reef, Australia, with Abudefduf whitleyi Allen & Robertson as the type-host. This taxon differs from the only other known member of the genus, Opechonoides gure Yamaguti, 1940, in the sucker width ratio, cirrus-sac length, position of the testes, position of the pore of Laurer's canal, and relative post-testicular distance. The new species exhibits stenoxenic host-specificity, infecting pomacentrids from seven genera: Abudefduf Forsskål, Amphiprion Bloch & Schneider, Neoglyphidodon Allen, Neopomacentrus Allen, Plectroglyphidodon Fowler & Ball, Pomacentrus Lacépède and Stegastes Jenyns. Phylogenetic analyses of 28S rDNA sequence data demonstrate that O. opisthoporus n. sp. forms a strongly supported clade with Prodistomum orientale (Layman, 1930) Bray & Gibson, 1990. The life cycle of this new species is partly elucidated on the basis of ITS2 rDNA sequence data; intermediate hosts are shown to be three species of Ctenophora. New host records and molecular data are reported for Lepocreadium oyabitcha Machida, 1984 and Lepotrema amblyglyphidodonis Bray, Cutmore & Cribb, 2018, and new molecular data are provided for Lepotrema acanthochromidis Bray, Cutmore & Cribb, 2018 and Lepotrema adlardi (Bray, Cribb & Barker, 1993) Bray & Cribb, 1996. Novel cox1 mtDNA sequence data showed intraspecific geographical structuring between Heron Island and Lizard Island for L. acanthochromidis but not for L. adlardi or O. opisthoporus n. sp.

Finding a needle in a haystack: larval stages of Didymozoidae (Trematoda: Digenea) parasitizing marine zooplankton

Abstract: 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.

First record of Derogenes varicus and Dinurus scombri (Digenea: Hemiurata) from Red Sea fishes, Yemen

Abstract: Two widely distributed and economically important food fish in the Red Sea were investigated. A total of 101 specimens of Epinephelus tauvina and 120 Abalistes stellatus were collected from Al-Mehwat local fish market, Hodeidah City, Yemen, between October 2009 and April 2010 and examined for their parasites. Two digenean species of the suborder Hemiurata, namely Derogenes varicus (Müller, 1784) and Dinurus scombri Yamaguti, 1934, were found in these fishes. The former parasite occurred in 15% of A. stellatus and 4% of E. tauvina and its mean intensity of infection was 4.2 and 3.5, respectively while the abundance was 15 and 4, respectively. The latter parasite occurred only in 1% of E. tauvina, with a mean intensity of 2 and an abundance of 0.02. The present study represents the first record of these two parasite species in Yemeni waters of the Red Sea. In addition, E. tauvina now represents a new host for D. scombri.

A new genus of diplostomids (digenea: diplostomoidea) from the nile crocodile in south africa with a key to diplostomid genera.

Abstract: The Diplostomidae Poirier, 1886 is a large family of digeneans within the superfamily Diplostomoidea Poirier, 1886. Members of the family are distributed worldwide and parasitize a diversity of tetrapod definitive hosts. Notably, only 2 mature diplostomids are known from crocodilians and both are suggested to be accidental infections. In this study, we use morphological and molecular data to describe Neofibricola n. gen. from a Nile crocodile Crocodylus niloticus collected in South Africa. We provide a description of adults and metacercariae of the type species, Neofibricola smiti n. sp., and metacercariae of a likely congeneric species. We generated partial 28S and internal transcribed spacer region ribosomal deoxyribonucleic acid (DNA) and cytochrome c oxidase 1 subunit mitochondrial DNA for both species and utilized the newly generated 28S sequences to examine phylogenetic affinities of these new taxa. In addition, we provide a new key to diplostomid genera, considering the substantial systematic changes and newly erected genera since the previously published key to diplostomid genera.

Temporal effects and changes in the parasitic community of <i>Prochilodus lineatus</i> (Valenciennes, 1837) (Characiformes: Prochilodontidae) in a floodplain

Abstract: The construction of dams causes several impacts on aquatic environments, altering the flow of rivers, environmental variables, and all biota present, including parasites. Little is known about how the parasitic community can be influenced in the long term by environmental changes. In this study, it was expected that the impacts caused by environmental disturbances will be directly reflected by the composition of the parasite populations. We evaluated the change in the structure of the Prochilodus lineatus endoparasite community between two periods sampled 15 years apart in the upper Paraná River floodplain. There was a significant difference in the weight-length relationship of P. lineatus between these periods and a total of 15 species of parasites were found: 11 species in Period 1 and nine species in Period 2 and five species occurred in both periods. The species richness and diversity were higher in Period 1, and we observed that the correlation of descriptors (richness, diversity and evenness) increased with fish length in this period. In both periods, digeneans numerically dominated the parasitic community, and we verified changes in the composition of parasites between periods. Both the host and the parasites were possibly affected by the environmental impacts resulting from the construction of dams over time, and it is noteworthy that complex life cycle parasites such as Digenea and Acanthocephala require intermediate hosts to complete their life cycle, and the population responds to fluctuations in the face of modified environments.

Molecular Characterization of the First Reported Neoplagioglyphe megastomus (Digenea, Omphalometridae) in Poland

Abstract: The diversity and taxonomy of metacercariae infecting freshwater amphipods of Poland are predominantly poorly known. During parasitological surveys of Gammarus pulex (Crustacea: Amphipoda) in the Pomeranian region of Poland in 2020 and 2021, some specimens of crustaceans were found to harbour metacercariae. Out of seven observed localities, metacercariae were found in the stream close to Krępa Słupska and the Lupawa River close to Smoldzino. They were morphologically studied and sequenced using universal eukaryotic primers that amplify V4–V5 regions of 18S rRNA. The BLAST analysis and phylogenetic reconstructions aid to define the affiliation of the revealed metacercariae within the Omphalometridae Looss, 1899. The further differential analysis based on morphologic information led to the conclusion that the metacercarial form studied herein represents Neoplagioglyphe megastomus (Baer, 1943). The degree of morphometric variations of taxonomic important features in populations from different geographic regions was followed up. The reported here form was characterized by a larger body size that was affected by the processing methods used in the present and previous studies. To our knowledge, this is the first report of Neoplagioglyphe megastomus in Poland and is the first molecular characterization of the worm

Philophthalmus hechingeri n. sp. (Digenea: Philophthalmidae), a Human-Infecting Eye Fluke from the Asian Mud Snail, Batillaria attramentaria

Abstract: ABSTRACT Two cases of human philophthalmosis have been reported in Japan. Gravid flukes removed from the eyes of the patients were broken, but their morphological characteristics suggest that an unknown species of the genus Philophthalmus is involved as a pathogen for humans. The mitochondrial DNA barcode of the human eye fluke enabled us to discover its larval stage from the Japanese mud snail, Batillaria attramentaria. The discovered cercaria had previously been temporarily described as “Philophthalmid sp. I.” In this study, we examined the infection status of B. attramentaria with Philophthalmid sp. I found on a muddy seashore of the Seto Inland Sea, Japan, and the resulting metacercariae were experimentally administered to Japanese quails to develop them into the gravid adult stage. The complete specimens of the adult and larval stages allowed us to describe a new species. Based on morphological and molecular analyses, Philophthalmus hechingeri n. sp. is proposed for the human-infecting eye fluke in Japan. The natural definitive hosts of the new species are unknown. However, the habitat of B. attramentaria suggests that shorebirds (seagulls, sandpipers, and plovers) might be the possible candidates.

Digenea nana sp. nov. (Rhodomelaceae, Rhodophyta), a new turf-forming, coral reef species from the Western Tropical Atlantic

Abstract: ABSTRACT The number of newly described species has increased since the addition of molecular data to taxonomic studies, revealing that species considered widely distributed by morphological and anatomical studies are often comprised of complexes of several distinct species. This study reports on a new turf-forming species of Digenea from the Greater Caribbean (South Florida and eastern Cuba), previously identified as D. simplex based on morpho-anatomical characters, but shown through DNA sequences to be a distinct species. Digenea nana sp. nov. is characterized by its small brush appearance, small dimensions (2.5 cm high and 0.6 mm wide), long determinate branches reaching 15 mm in length (its most striking feature) and 11–12 pericentral cells. Digenea nana is distinct from all its congeners, showing sequence divergences of 3.5–5.0% in COI-5P and 1.7–2.7% in rbcL. The species resolved as sister to D. rafaelii (genetic distance of about 3.5% and 1.7% in COI-5P and rbcL respectively) from Pacific Mexico, and can be easily distinguished by morpho-anatomical characters. Digenea nana is the seventh species in the genus worldwide. Given the presumed wide distribution of D. simplex, based solely on morpho-anatomy, and the number of cryptic and pseudo-cryptic species recently described, further integrative molecular and morpho-anatomical studies are likely to reveal new taxa.

Dolichoperoides macalpini (Nicoll, 1914) (Digenea: Dolichoperoididae) infecting venomous snakes (Elapidae) across Australia: molecular characterisation and infection parameters

Abstract: Specimens of Dolichoperoides macalpini (Nicoll, 1914) (Digenea: Dolichoperoididae) were collected from Australian venomous snakes (Elapidae): Notechis scutatus Peters, 1861 and Austrelaps superbus (Günther, 1858) from Tasmania and surrounding islands and N. s. occidentalis Glauert, 1948 from wetlands near Perth, Western Australia. Despite variation in morphological measurements, genetic analysis showed that the one species of digeneans infected the snakes from all locations. This study presents the first DNA sequences for D. macalpini (internal transcribed spacer, 18S, 28S), confirming its placement in a family separate from the Reniferidae and Telorchiidae. Analysis of the infection dynamics of infection in Western Australian snakes showed significant differences in levels of infection between wetland locations, season and year of collection. Infection of D. macalpini was reported in the gastrointestinal tract, including the mouth, in freshly euthanised snakes in Western Australia, and in the lung in Tasmanian snakes, consistent with earlier reports. Differences in morphology and site of infection are suggested to be due to a combination of season and maturity of the digenean, with infection potentially occurring early in the season, as the snakes emerge from torpor. The need for research on the seasonal dynamics of infection with this parasite is discussed.

A new species of Auriculostoma (Digenea: Allocreadiidae) in South America: life cycle and phylogenetic relationships

Abstract: Auriculostoma is a genus of digenean (Trematoda) whose adults are parasites of Neotropical freshwater fishes. We describe Auriculostoma ocloya n. sp. using morphological and molecular tools, and we elucidated its life cycle, the first known of a species of this genus. The first intermediate host is the bivalve Pisidium ocloya, the second intermediate host is the amphipod Hyalella sp., and the definite hosts are siluriform fishes. The adult presents a single pair of muscular lobes on either side of the oral sucker with a broad base, stretching from ventrolateral to dorsolateral side, a structure also present in the rest of species of the genus. Nevertheless, the new species differs from all congeners by the combination of several traits, and mainly because on the dorsal side "free" ends of the lobes are absent because they are fused. This is the first study to provide sequence data on larval and adult stages of a species of Auriculostoma. Our phylogenetic analysis demonstrated its basal position among species of the genus. Therefore, integrative morphological, molecular, and life cycle data on other South American species of the genus, would contribute to reveal more patterns in the allocreadiid systematics.

First record of metacercariae trematodes Opisthioglyphe ranae (Digenea: Telorchiidae) and Echinostoma bolschewense (Digenea: Echinostomatidae) in Dreissena polymorpha (Bivalvia: Dreissenidae) from the Don and Volga river basins, Russia

Abstract: It is well known that an invasive bivalve mollusk species Dreissena polymorpha plays a significant role as a host to parasites. Currently, the interaction between digenean trematodes and their bivalve hosts remains relatively poorly understood. In this study we investigate infection of D. polymorpha by trematodes using molecular genetics, histological, and light microscopy methods. We obtained sequences of one mitochondrial (molecular cytochrome c oxidase subunit 1 (COI)) and two nuclear (ITS2, rDNA 28S) gene markers. To the best of our knowledge, this is the first time that infection of metacercariae of Opisthioglyphe ranae and Echinostoma bolschewense in D. polymorpha has been detected. Our sequence was 100% identical to the 28S rDNA of the species O. ranae recorded in Penza Oblast (Russia) in pond frog. At the same time, some sequences of the 28S rDNA of O. ranae detected in Penza Oblast (Russia) and Ivano-Frankovsk Region (Ukraine) were different from our sequence by 0.2%. Our sequence was 100% identical to the 28S rDNA of the species E. bolschewense sequenced in Slovakia. In addition, we received sequences of COI for both trematode species and ITS2 of E. bolschewense for the first time.

Molecular Diversity of Diplostomum spathaceum (Digenea: Diplostomidae) on the Capoeta umbla and Cyprinus carpio (Cypriniformes) Using Mitochondrial DNA Barcode

Abstract: Diplostomid trematodes (Digenea) include a wide and diverse group of common digeneans. Diplostomid larval stages are significant pathogens that may exert grave effects on both natural fish and aquaculture populations. Diplostomum species, which use fish as a second intermediate host, is one of the most common trematode species, which affects the fish welfare negatively with the formation of cataracts by settling in the eye. This study is determined the molecular characterization of Diplostomum parasite in Cyprinus carpio and Capoeta umbla for the first time from Turkey, based on the mitochondrial COX1 sequence data. Diplostomum samples were determined as Diplostomum spathaceum according to the phylogenetic trees created in the light of the morphological and COX1 sequence data. Sequence results matched ~98-100% with D. spathaceum as a result of blast analysis. It was defined that this parasite was represented by three different haplotypes in Turkey. As a result of haplotype analysis performed on a total of 162 isolates in GenBank and obtained in this study, 40 polymorphic regions and 58 haplotypes were determined. This haplotype network had arranged within a star-like configuration with a main central haplotype. This shows that the variation within D. spathaceum species is quite high. The mean abundance, mean intensity, and prevalence of the parasite in C. carpio were 8.29 (5.80-11.24), 10.91±9.37 (1-39), and 76%, respectively. In the C umbla, mean abundance, mean intensity, and prevalence were calculated as 11.54 (10.16-12.92), 14.07±16.59 (1-67), and 82%, respectively.

Ultrastructural and molecular study of the microsporidian Toguebayea baccigeri n. gen., n. sp., a hyperparasite of the digenean trematode Bacciger israelensis (Faustulidae), a parasite of Boops boops (Teleostei, Sparidae)

Abstract: A new microsporidian Toguebayea baccigeri n. gen., n. sp., hyperparasite of Bacciger israelensis (Digenea, Faustulidae), parasite of Boops boops (Teleostei, Sparidae) is described by means of transmission electron microscopy. The phylogenetic analysis, based on the SSU rDNA gene, places the new species in the clade containing mainly crustacean-infecting microsporidia of the genus Cucumispora, within superclade V (Marinosporidia) sensu Vossbrinck et al., 2014. Mature spores of T. baccigeri are ovoid, uninucleated and measure 2.5 × 1.4 μm. The number of coils of the polar tube is 8–10. The polaroplast is composed of an external lamellar part and an internal vesicular or granular part. The main differences that distinguish the new genus and new species from the closely related microsporidia include hyperparasitism in a digenean host infecting a marine fish, the geographic distribution (coast of Tunisia), presence of one nucleus at all developmental stages, disporoblastic sporogony, and the absence of sporophorous vacuoles.