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Parasitology International Dec 2023Species of the genus Pseudoterranova, infect kogiid cetaceans and pinnipeds. However, there is mounting molecular evidence that those from cetaceans and pinnipeds are...
Resurrection of genus Phocanema Myers, 1959, as a genus independent from Pseudoterranova Mozgovoĭ, 1953, for nematode species (Anisakidae) parasitic in pinnipeds and cetaceans, respectively.
Species of the genus Pseudoterranova, infect kogiid cetaceans and pinnipeds. However, there is mounting molecular evidence that those from cetaceans and pinnipeds are not congeneric. Here, we provide further evidence of the non-monophyly of members of Pseudoterranova from phylogenetic analyses of the conserved nuclear LSU rDNA gene, entire ITS rDNA region and mtDNA cox2 gene, and identify morphological characters that may be used to distinguish the members of the two clades. We propose the resurrection of the genus Phocanema, with Ph. decipiens (sensu stricto) as the type species, to encompass Ph. decipiens, Ph. azarasi, Ph. bulbosa, Ph. cattani and Ph. krabbei, all parasites of pinnipeds. We propose to restrict the conception of genus Pseudoterranova, which now harbours two species infecting kogiid whales; Ps. kogiae (type species) and Ps. ceticola. Members of the genera Phocanema and Pseudoterranova differ by the shape and orientation of the lips, relative tail lengths, adult size, type of final host (pinniped vs. cetacean) and phylogenetic placement based on nuclear rDNA and mtDNA cox2 sequences.
Topics: Animals; Caniformia; Parasites; Phylogeny; Cyclooxygenase 2; Ascaridoidea; DNA, Ribosomal; Whales; DNA, Mitochondrial
PubMed: 37573003
DOI: 10.1016/j.parint.2023.102794 -
International Journal of Food... Apr 2021Anisakid nematode larvae (NL) in fish products comprise a risk to human health and, if visible, lead to the rejection of these products by consumers. Therefore, great... (Review)
Review
Anisakid nematode larvae (NL) in fish products comprise a risk to human health and, if visible, lead to the rejection of these products by consumers. Therefore, great efforts are being made for the identification of these anisakid larvae to estimate the potential consumer health risk as well as to develop effective detection methods in order to prevent the introduction of heavily infected fish products into the market. The tasks of national reference laboratories include the improvement of detection methods and to promote their further development. As a prerequisite for improved detection, it is important to understand the structural properties of anisakid NL and compounds produced during host-parasite interactions. This review provides an overview of the intrinsic properties of anisakid NL and reports the latest detection methods in published literature. First, in order to define the potentially interesting intrinsic properties of anisakid nematodes for their detection, anatomy and compounds involved in host-parasite interactions are summarised. These can be used for various detection approaches, such as in the medical field or for allergen detection in fish products. In addition, fluorescence characteristics and their use as both established and promising candidates for detection methods, especially in the field of optical sensing technologies, are presented. Finally, different detection and identification methods applied by the fish processing industries and by control laboratories are listed. The review intends to highlight trends and provide suggestions for the development of improved detection and identification methods of anisakid NL in fish products.
Topics: Animals; Anisakiasis; Anisakis; Fish Products; Fluorescence; Food Microbiology; Food-Processing Industry; Host-Parasite Interactions; Humans; Larva
PubMed: 33621832
DOI: 10.1016/j.ijfoodmicro.2021.109094 -
Folia Parasitologica May 2023Evolutionary and ecological processes affecting the interactions between hosts and parasites in the aquatic environment are at display in the Baltic Sea, a young and...
Evolutionary and ecological processes affecting the interactions between hosts and parasites in the aquatic environment are at display in the Baltic Sea, a young and ecologically unstable marine ecosystem, where fluctuating abiotic and biotic factors affect the parasitofauna in fish. The dynamic infections of Baltic cod, a subpopulation of the Atlantic cod (Gadus morhua Linnaeus), with third stage anisakid nematode larvae of Pseudoterranova decipiens (Krabbe, 1878) and Contracaecum osculatum (Rudolphi, 1802) have increased following a significant increase of the Baltic grey seal Halichoerus grypus (Fabricius) population in the region. Cod serves as a paratenic host and marine mammals, pinnipeds, are definitive hosts releasing parasite eggs, with faeces, to the marine environment, where embryonation and hatching of the third stage larva take place. The parasite has no obligate intermediate hosts, but various invertebrates, smaller fish and cod act as paratenic hosts transmitting the infection to the seal. Contracaecum osculatum has an impact on the physiological performance of the cod, which optimises transmission of the larva from fish to seal. Thus, a muscle mass decrease of nearly 50% may result from heavy C. osculatum infections, probably amplified by a restricted food availability. The muscle atrophy is likely to reduce the escape reactions of the fish when meeting a foraging seal. In certain regions, where fish and seals are restricted in their migration patterns, such as the semi-enclosed Baltic Sea, the predation may contribute to a severe cod stock depletion. The parasites are zoonotic and represent a human health risk, when consumers ingest insufficiently heat- or freeze-treated infected products. Marked infections of the cod were previously reported during periods with elevated seal populations (late 19th and middle 20th century) and various scenarios for management of risk factors are evaluated in an evolutionary context.
Topics: Humans; Animals; Parasites; Ecosystem; Fishes; Seals, Earless; Larva; Ascaridoidea; Gadus morhua; Fish Diseases
PubMed: 37265200
DOI: 10.14411/fp.2023.011 -
Parasitology Jul 2022In the Anisakidae family, there are nematodes, most of which are parasitic for important commercial fish species. Both public health risks and socio-economic problems...
In the Anisakidae family, there are nematodes, most of which are parasitic for important commercial fish species. Both public health risks and socio-economic problems are attributed to these parasites. Despite these concerns, knowledge of the metabolism of these parasites remains unknown. Therefore, the main objective of this study was to investigate the receptors of drugs and oxidative metabolic status of two Anisakidae species, (s. s.) and (s. s.), under the influence of anthelminthic drugs, ivermectin (IVM) and pyrantel (PYR), at different concentrations: 1.56, 3.125 and 6.25 g mL of culture medium for 3, 6, 9, 12 and 72 h. The mRNA expressions of the -aminobutyric acid receptor, acetylcholine receptor subunits, adenosine triphosphate-binding cassette transporters and antioxidative enzymes were determined. The total antioxidant capacity and glutathione -transferase activity were also examined. To the best of the authors' knowledge, this is the first time that IVM and PYR have been tested against these parasitic nematodes.
Topics: Animals; Ascaridoidea; Fish Diseases; Fishes
PubMed: 35443901
DOI: 10.1017/S0031182022000543 -
Acta Parasitologica Mar 2022Studies of parasite communities and patterns in the Antarctic are an important knowledge base with the potential to track shifts in ecological relations and study the...
BACKGROUND
Studies of parasite communities and patterns in the Antarctic are an important knowledge base with the potential to track shifts in ecological relations and study the effects of climate change on host-parasite systems. Endemic Nototheniinae is the dominant fish group found in Antarctic marine habitats. Through their intermediate position within the food web, Nototheniinae link lower to higher trophic levels and thereby also form an important component of parasite life cycles. The study was set out to gain insight into the parasite fauna of Nototheniops larseni, N. nudifrons and Lepidonotothen squamifrons (Nototheniinae) from Elephant Island (Antarctica).
METHODS
Sampling was conducted at three locations around Elephant Island during the ANT-XXVIII/4 expedition of the research vessel Polarstern. The parasite fauna of three Nototheniine species was analysed, and findings were compared to previous parasitological and ecological research collated from a literature review.
RESULTS
All host species shared the parasites Neolebouria antarctica (Digenea), Corynosoma bullosum (Acanthocephala) and Pseudoterranova decipiens E (Nematoda). Other parasite taxa were exclusive to one host species in this study. Nototheniops nudifrons was infected by Ascarophis nototheniae (Nematoda), occasional infections of N. larseni with Echinorhynchus petrotschenkoi (Acanthocephala) and L. squamifrons with Elytrophalloides oatesi (Digenea) and larval tetraphyllidean Cestoda were detected.
CONCLUSION
All examined fish species' parasites were predominantly euryxenous regarding their fish hosts. The infection of Lepidonotothen squamifrons with Lepidapedon garrardi (Digenea) and Nototheniops larseni with Echinorhynchus petrotschenkoi represent new host records. Despite the challenges and limited opportunities for fishing in remote areas, future studies should continue sampling on a more regular basis and include a larger number of fish species and sampling sites within different habitats.
Topics: Animals; Antarctic Regions; Ascaridoidea; Fish Diseases; Host-Parasite Interactions; Parasites; Perciformes; Trematoda
PubMed: 34275092
DOI: 10.1007/s11686-021-00455-8 -
Journal of Fish Diseases Aug 2022The recent advances in molecular methods and data processing have facilitated research on anisakid nematodes. While most research efforts were made regarding the genus...
The recent advances in molecular methods and data processing have facilitated research on anisakid nematodes. While most research efforts were made regarding the genus Anisakis, since this genus is held responsible for the majority of reported clinical signs, there is still a demand for data on the genus Pseudoterranova. Several case studies of severe invasive anisakidosis affecting various organs caused by species of the P. decipiens complex have been described. To better understand the way these parasites might infest their fish host, we examined whether parasite location within the fish host affects gene expression. A de novo assembly of the transcriptome of Pseudoterranova bulbosa, isolated from North Atlantic cod, was analysed for patterns of differential gene expression between samples taken from liver and viscera. We additionally searched for homologs to known nematode allergens, to give a first estimate of the potential allergenicity of P. bulbosa. There was a subtle difference in the gene expression of samples taken from liver and viscera. Seventy genes were differentially expressed, 32 genes were upregulated in parasites isolated from liver and 38 genes were upregulated in parasites from viscera. Homologs of five nematode allergens were identified among the genes expressed by P. bulbosa. Our transcriptome of P. bulbosa will be a valuable resource for further meta-analyses and resequencing projects.
Topics: Allergens; Animals; Anisakis; Ascaridoidea; Communicable Diseases; Fish Diseases; Gadus morhua; Gene Expression; Larva
PubMed: 35475516
DOI: 10.1111/jfd.13630 -
Journal of Helminthology Sep 2020Pseudoterranoviasis is a zoonotic disease caused by nematode larvae of species within the genus Pseudoterranova (seal worm, cod worm). Most infections are...
Pseudoterranoviasis is a zoonotic disease caused by nematode larvae of species within the genus Pseudoterranova (seal worm, cod worm). Most infections are gastrointestinal, oesophageal or pharyngeal, but here we report a nasal infection. A 33-year-old patient suffering from rhinitis for 1.5 years recovered a worm larva from the nose. Diagnosis was performed by morphological and molecular characterization, showing the causative agent to be a third-stage larva of Pseudoterranova decipiens (sensu stricto). Various infection routes are discussed.
Topics: Adrenal Cortex Hormones; Adult; Animals; Ascaridida Infections; Ascaridoidea; Denmark; Humans; Larva; Male; Nose; Rhinitis, Allergic
PubMed: 32921327
DOI: 10.1017/S0022149X20000681 -
Parasitology Dec 2022Northeast Arctic cod, saithe and haddock are among the most important fisheries resources in Europe, largely shipped to various continental markets. The present study...
Anisakid parasites (Nematoda: Anisakidae) in 3 commercially important gadid fish species from the southern Barents Sea, with emphasis on key infection drivers and spatial distribution within the hosts.
Northeast Arctic cod, saithe and haddock are among the most important fisheries resources in Europe, largely shipped to various continental markets. The present study aimed to map the presence and distribution of larvae of parasitic nematodes in the Anisakidae family which are of socioeconomic and public health concern. Fishes were sourced from commercial catches during winter or spring in the southern Barents Sea. Samples of fish were inspected for nematodes using the UV-press method while anisakid species identification relied on sequencing of the mtDNA gene. (s.s.) was the most prevalent and abundant anisakid recorded, occurring at high infection levels in the viscera and flesh of cod and saithe, while being less abundant in haddock. (s.l.) larvae, not found in the fish flesh, showed moderate-to-high prevalence in saithe, haddock and cod, respectively. Most spp. larvae occurred at low-to-moderate prevalence, and low abundance, in the viscera () and flesh ( (s.s.) and ) of cod, only 2 (s.s.) appeared in the flesh of saithe. Body length was the single most important host-related factor to predict overall abundance of anisakid larvae in the fish species. The spatial distribution of larvae in the fish flesh showed much higher abundances in the belly flaps than in the dorsal fillet parts. Trimming of the flesh by removing the belly flaps would reduce larval presence in the fillets of these gadid fish species by 86–91%.
Topics: Animals; Parasites; Fish Diseases; Ascaridoidea; Anisakis; Fishes; Larva; Gadiformes; Anisakiasis
PubMed: 36321524
DOI: 10.1017/S0031182022001305 -
Revista Brasileira de Parasitologia... 2019The current parasitological study was carried out to investigate helminth parasites infecting the Red spot emperor Lethrinus lentjan inhabiting Hurghada City at the Gulf...
The current parasitological study was carried out to investigate helminth parasites infecting the Red spot emperor Lethrinus lentjan inhabiting Hurghada City at the Gulf of Suez, Red Sea, Egypt. Third-stage larvae of nematode parasite was isolated from the intestine as well as body cavity of the examined fish. Light and scanning electron microscopy revealed that this parasite belonged to Anisakidae family within the genus Pseudoterranova. The present species is named Pseudoterranova decipiens based on the presence of triangular mouth aperture with prominent boring teeth and soft swellings of the cuticle, long muscular esophagus, ventrally excretory pore, and narrow transverse slit of anal opening followed by a short mucron. The morphological characteristics of this species were confirmed by molecular analysis of 18S rDNA gene region of the present parasite. It demonstrated a close identity ≥89% with taxa under family Anisakidae, 85% with Raphidascarididae, and 79-84% with Toxocaridae. A preliminary genetic comparison between gene sequence of the present parasite and other oxyurid species placeed it as a putative sister taxon to other Pseudoterranova decipiens described previously. This study demonstrated that the 18S rDNA gene region of Pseudoterranova decipiens yielded a unique sequence that confirmed its taxonomic position in Anisakidae.
Topics: Animals; DNA, Ribosomal; Egypt; Fish Diseases; Fishes; Indian Ocean; Microscopy, Electron, Scanning; Nematoda; Phylogeny; RNA, Ribosomal, 18S
PubMed: 31460624
DOI: 10.1590/S1984-29612019057 -
International Journal For Parasitology.... Aug 2020Harbour porpoises () are the only native cetacean species in the German North and Baltic Seas and the final host of (.) , which infects their first and second gastric...
Harbour porpoises () are the only native cetacean species in the German North and Baltic Seas and the final host of (.) , which infects their first and second gastric compartments and may cause chronic ulcerative gastritis. belongs to the family Anisakidae (Ascaridoidea, Rhabditida) as well as the phocine gastric nematode species (.) and (.) . These nematode species are the main causative agents for the zoonosis anisakidosis. The taxonomy of these genus with life cycles including crustaceans and commercially important fish is complex because of the formation of sibling species. Little is known about anisakid species infecting porpoises in the study area. Mature nematodes and larval stages are often identifiable only by molecular methods due to high morphological and genetic similarity. The restriction fragment length polymorphism (RFLP) method is an alternative to sequencing and was applied to identify anisakid nematodes found in harbour porpoises from the North Sea, Baltic Sea and North Atlantic to species level for the first time. In the study areas, five gastric nematodes from different harbour porpoise hosts were selected to be investigated with restriction enzymes I, I and III, which were able to differentiate several anisakid nematode species by characteristic banding patterns. s. s. was the dominant species found in the North Sea and Baltic porpoises, identified by all three restriction enzymes. Additionally, a hybrid of . s. s. and . was determined by I in the North Sea samples. Within the North Atlantic specimens, . s. s., . s. s. and (.) were identified by all enzymes. This demonstrates the value of the RFLP method and the chosen restriction enzymes for the species identification of a broad variety of anisakid nematodes affecting the health of marine mammals.
PubMed: 32489854
DOI: 10.1016/j.ijppaw.2020.05.004