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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 -
Parasites & Vectors Feb 2020Red Vent Syndrome (RVS), a haemorrhagic inflammation of the vent region in Atlantic salmon, is associated with high abundance of Anisakis simplex (s.s.) third-stage...
BACKGROUND
Red Vent Syndrome (RVS), a haemorrhagic inflammation of the vent region in Atlantic salmon, is associated with high abundance of Anisakis simplex (s.s.) third-stage larvae (L3) in the vent region. Despite evidence suggesting that increasing A. simplex (s.s.) intensity is a causative factor in RVS aetiology, the definitive cause remains unclear.
METHODS
A total of 117 Atlantic salmon were sampled from commercial fisheries on the East, West, and North coasts of Scotland and examined for ascaridoid parasites. Genetic identification of a subsample of Anisakis larvae was performed using the internal transcribed spacer (ITS) region of ribosomal DNA. To assess the extent of differentiation of feeding grounds and dietary composition, stable isotope analysis of carbon and nitrogen was carried out on Atlantic salmon muscle tissue.
RESULTS
In the present study, the obtained ITS rDNA sequences matched A. simplex (s.s.) sequences deposited in GenBank at 99-100%. Not all isolated larvae (n = 30,406) were genetically identified. Therefore, the morphotype found in this study is referred to as A. simplex (sensu lato). Anisakis simplex (s.l.) was the most prevalent (100%) nematode with the highest mean intensity (259.9 ± 197.3), in comparison to Hysterothylacium aduncum (66.7%, 6.4 ± 10.2) and Pseudoterranova decipiens (s.l.) (14.5%, 1.4 ± 0.6). The mean intensity of A. simplex (s.l.) represents a four-fold increase compared to published data (63.6 ± 31.9) from salmon captured in Scotland in 2009. Significant positive correlations between A. simplex (s.l.) larvae intensities from the body and the vent suggest that they play a role in the emergence of RVS. The lack of a significant variation in stable isotope ratios of Atlantic salmon indicates that diet or feeding ground are not driving regional differences in A. simplex (s.l.) intensities.
CONCLUSIONS
This paper presents the most recent survey for ascaridoid parasites of wild Atlantic salmon from three coastal regions in Scotland. A significant rise in A. simplex (s.l.) intensity could potentially increase both natural mortality rates of Atlantic salmon and possible risks for salmon consumers due to the known zoonotic role of A. simplex (s.s.) and A. pegreffii within the A. simplex (s.l.) species complex.
Topics: Animals; Anisakiasis; Anisakis; DNA, Intergenic; DNA, Ribosomal; Fish Diseases; Larva; Salmo salar; Scotland; Seafood
PubMed: 32051019
DOI: 10.1186/s13071-020-3942-5 -
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 -
Scientific Reports Jul 2019Environmental niche modelling is an acclaimed method for estimating species' present or future distributions. However, in marine environments the assembly of...
Environmental niche modelling is an acclaimed method for estimating species' present or future distributions. However, in marine environments the assembly of representative data from reliable and unbiased occurrences is challenging. Here, we aimed to model the environmental niche and distribution of marine, parasitic nematodes from the Pseudoterranova decipiens complex using the software Maxent. The distribution of these potentially zoonotic species is of interest, because they infect the muscle tissue of host species targeted by fisheries. To achieve the best possible model, we used two different approaches. The land distance (LD) model was based on abiotic data, whereas the definitive host distance (DHD) model included species-specific biotic data. To assess whether DHD is a suitable descriptor for Pseudoterranova spp., the niches of the parasites and their respective definitive hosts were analysed using ecospat. The performance of LD and DHD was compared based on the variables' contribution to the model. The DHD-model clearly outperformed the LD-model. While the LD-model gave an estimate of the parasites' niches, it only showed the potential distribution. The DHD-model produced an estimate of the species' realised distribution and indicated that biotic variables can help to improve the modelling of data-poor, marine species.
Topics: Animals; Aquatic Organisms; Ecosystem; Fisheries; Fishes; Host Specificity; Parasites; Species Specificity
PubMed: 31285445
DOI: 10.1038/s41598-019-46127-6 -
International Journal For Parasitology Jul 2019Human toxocariasis is a zoonosis resulting from the migration of larval stages of the dog parasite Toxocara canis into the human paratenic host. Despite its well-known...
Human toxocariasis is a zoonosis resulting from the migration of larval stages of the dog parasite Toxocara canis into the human paratenic host. Despite its well-known limitations, serology remains the most important tool to diagnose the disease. Our objective was to employ camelid single domain antibody fragments also known as nanobodies (Nbs) for a specific and sensitive detection of Toxocara canis excretory/secretory (TES) antigens. From an alpaca immune Nb library, we retrieved different Nbs with specificity for TES antigens. Based on ELISA experiments, these Nbs did not show any cross-reactivity with Ascaris lumbricoides, Ascaris suum, Pseudoterranova decipiens, Anisakis simplex and Angiostrongylus cantonensis larval antigens. Western blot and immunocapturing revealed that Nbs 1TCE39, 1TCE52 and 2TCE49 recognise shared epitopes on different components of TES antigen. The presence of disulphide bonds in the target antigen seems to be essential for recognition of the epitopes by these three Nbs. Three separate sandwich ELISA formats, using monovalent and bivalent Nbs, were assessed to maximise the detection of TES antigens in solution. The combination of biotinylated, bivalent Nb 2TCE49 on a streptavidin pre-coated plate to capture TES antigens, and Nb 1TCE39 chemically coupled to horseradish peroxidase for detection of the captured TES antigens, yielded the most sensitive ELISA with a limit of detection of 0.650 ng/ml of TES antigen, spiked in serum. Moreover, the assay was able to detect TES antigens in sera from mice, taken 3 days after the animals were experimentally infected with T. canis. The specific characteristics of Nbs make this ELISA not only a promising tool for the detection of TES antigens in clinical samples, but also for a detailed structural and functional study of TES antigens.
Topics: Animals; Antibodies, Helminth; Antigens, Helminth; Blotting, Western; Camelids, New World; Electrophoresis, Polyacrylamide Gel; Enzyme-Linked Immunosorbent Assay; Female; Humans; Male; Mice; Microspheres; Plasmids; Polymerase Chain Reaction; Single-Domain Antibodies; Toxocara canis
PubMed: 31150611
DOI: 10.1016/j.ijpara.2019.03.004 -
The Korean Journal of Parasitology Apr 2019Anisakiasis is a zoonotic disease induced by anisakid nematodes, and endoscopic inspection is used for a diagnosis or remedy for it. Anisakis simplex, Anisakis...
Anisakiasis is a zoonotic disease induced by anisakid nematodes, and endoscopic inspection is used for a diagnosis or remedy for it. Anisakis simplex, Anisakis physeteris, and Pseudoterranova decipiens had been reported to be the major species causing human infections, particularly, in Japan. However, in Korea, recent studies strongly suggested that Anisakis pegreffii is the major species of human infections. To support this suggestion, we collected anisakid larvae (n=20) from 20 human patients who were undergone gastrointestinal endoscopy at a health check-up center in Korea, and molecular identification was performed on the larvae using PCR-RFLP analysis and gene sequencing of rDNA ITS regions and mtDNA cox2. In addition, anisakid larvae (n=53) collected from the sea eel (Astroconger myriaster) were also examined for comparison with those extracted from humans. The results showed that all human samples (100%) were identified as A. pegreffii, whereas 90.7% of the samples from the sea eel were A. pegreffii with the remaining 9.3% being Hysterothylacium aduncum. Our study confirmed that A. pegreffii is the predominant species causing human anisakiasis in Korea, and this seems to be due to the predominance of this larval type in the fish (sea eels) popularly consumed by the Korean people. The possibility of human infection with H. aduncum in Korea is also suggested.
Topics: Adult; Aged; Animals; Anisakiasis; Anisakis; Cyclooxygenase 2; DNA, Mitochondrial; DNA, Ribosomal Spacer; Eels; Endoscopy, Gastrointestinal; Female; Fish Diseases; Humans; Larva; Male; Middle Aged; Molecular Diagnostic Techniques; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Republic of Korea; Sequence Analysis, DNA
PubMed: 31104416
DOI: 10.3347/kjp.2019.57.2.207 -
Parasitology Research Jul 2019The consumption of raw or inadequately cooked marine fish can lead to several disorders caused by the ingestion of viable anisakid nematodes. Although anisakid larvae...
The consumption of raw or inadequately cooked marine fish can lead to several disorders caused by the ingestion of viable anisakid nematodes. Although anisakid larvae can be killed by subzero temperatures, making freezing an important control measure for this potential health hazard, these parasites can survive freezing under some conditions. Therefore, the aim of the present study was to experimentally evaluate the time-temperature conditions needed to kill Anisakis simplex and Pseudoterranova spp. The effectiveness of freezing was tested on two species of fish: cod, Gadus morhua from the North Atlantic, and herring, Clupea harengus membras from the southern Baltic Sea. Samples, which comprised skinless fillets of cod (n = 40) with visible parasites and whole herring (n = 240), were separately frozen at - 15, - 18, or - 20 °C for 24 h, or at - 20 °C for 48 h in the single-compressor freezer and at - 20, - 25, or - 35 °C for 24 h in the double-compressor freezer. After thawing, parasites were stained with malachite green and examined under the microscope for viability. All A. simplex and Pseudoterranova spp. larvae in cod fillets died at a temperature of - 15 °C or lower. However, freezing did not kill all the A. simplex larvae in whole herring: spontaneous movement of these parasites was observed in samples stored in the single-compressor freezer at - 15, - 18, and - 20 °C over 24 h. Our results demonstrate that the freezing procedure must consider both the capability of the freezing device and the nature of the fish product to ensure consumer safety.
Topics: Animals; Anisakis; Ascaridoidea; Cold Temperature; Fish Diseases; Fishes; Food Safety; Foodborne Diseases; Freezing; Gadus morhua; Humans; Larva
PubMed: 31098726
DOI: 10.1007/s00436-019-06339-1 -
Experimental Parasitology Feb 2019Serodiagnosis of human anisakidosis is presently hampered by the current lack of standardised serological assays that allow sensitive and specific detection of... (Comparative Study)
Comparative Study
Comparative analysis of excretory-secretory antigens of Anisakis simplex, Pseudoterranova decipiens and Contracaecum osculatum regarding their applicability for specific serodiagnosis of human anisakidosis based on IgG-ELISA.
Serodiagnosis of human anisakidosis is presently hampered by the current lack of standardised serological assays that allow sensitive and specific detection of Anisakidae-specific antibodies in human patients. In the present study, we comparatively evaluated the diagnostic value (by IgG-ELISA) of excretory-secretory antigens (ESAgs) of Anisakis simplex, Pseudoterranova decipiens and Contracaecum osculatum, representing the most frequently found genera responsible for human infection. In addition, we tested also a mix of the three ES preparations (Mix-ESAgs) as well as two recombinant allergens of A. simplex, rAni s 1 and rAni s 7. ES antigen from C. osculatum yielded the best diagnostic performance in IgG-ELISA-based serodiagnosis of the Spanish anisakidosis patients investigated in this study (relative serodiagnostic sensitivity 100%; specificity 89%) as compared to A. simplex ES-antigen (93% versus 57%) and P. decipiens (67% versus 93%) or a mix of the three ES antigens (100% versus 44%), respectively. Cross-reactions of C. osculatum ES antigen with serum-antibodies from patients suffering from other helminth infections were rare and were exclusively found with few sera from toxocariasis, ascariasis, and filariasis patients. The two recombinant allergens rAni s 1 and rAni s 7 did not prove sufficiently sensitive and specific in order to justify a further evaluation of these antigens regarding their suitability in IgG-ELISA-based serodiagnosis of human anisakidosis. In conclusion, the C. osculatum-ESAg-ELISA remains as key candidate to be further assessed for the serodiagnosis of symptomatic anisakidosis in different endemic regions.
Topics: Animals; Anisakis; Antibodies, Helminth; Antigens, Helminth; Ascaridida Infections; Ascaridoidea; Cross Reactions; Enzyme-Linked Immunosorbent Assay; Humans; Immunoglobulin G; Rabbits; Sensitivity and Specificity; Serologic Tests
PubMed: 30584924
DOI: 10.1016/j.exppara.2018.12.004 -
A case of hepatic anisakiasis caused by Pseudoterranova decipiens mimicking metastatic liver cancer.BMC Infectious Diseases Dec 2018Anisakid nematodes (Anisakis spp. or Pseudoterranova spp.) usually infect gastric or intestinal walls, while they rarely infect in extra-gastrointestinal sites of human...
BACKGROUND
Anisakid nematodes (Anisakis spp. or Pseudoterranova spp.) usually infect gastric or intestinal walls, while they rarely infect in extra-gastrointestinal sites of human body. Generally, Anisakis spp. larvae are highly infected in fish intermediate hosts, whereas Pseudoterranova spp. larvae are very rarely infected. To the best of our knowledge, there have been no reports which have documented cases of hepatic anisakiasis caused by Pseudoterranova spp. This report describes the first documented case of hepatic anisakiasis due to infection with Pseudoterranova decipiens and clinical features of the hepatic anisakiasis through literature review.
CASE PRESENTATION
The case was a 28-year-old man with prior history of malignancy who was found to have a hepatic mass mimicking metastatic liver tumor. A new low density area of 20 mm in diameter in liver segment 7 was found on follow-up CT. With suspicious diagnosis of metastatic liver cancer, laparoscopic partial hepatectomy was performed. A pathological examination revealed no evidence of malignancy, but showed necrotic granuloma with eosinophil infiltration and the presence of a larva with Y-shaped lateral cords, which are specific to anisakid larvae. The type of larva was identified as Pseudoterranova decipiens sensu lato using PCR of DNA purified from a fixed granuloma embedded in paraffin.
CONCLUSION
The present report is the first to discuss the case of a patient with hepatic anisakiasis caused by Pseudoterranova decipiens. Hepatic anisakiasis is a potential differential diagnosis for hepatic tumors and genetic identification with the PCR method was reliable for obtaining final diagnosis even when the larvae body in the resected specimen collapses with time.
Topics: Adult; Animals; Anisakiasis; Anisakis; Ascaridoidea; Diagnosis, Differential; Granuloma; Humans; Liver Diseases, Parasitic; Liver Neoplasms; Male; Neoplasm Metastasis; Polymerase Chain Reaction
PubMed: 30514220
DOI: 10.1186/s12879-018-3540-8 -
International Journal For Parasitology.... Dec 2018The population of California sea lion (CSL) has steadily increased during the last several decades. Despite extensive research addressing CSL biology and ecology...
The population of California sea lion (CSL) has steadily increased during the last several decades. Despite extensive research addressing CSL biology and ecology performed during the last decades, there has been a minimal number of published papers documenting their parasite fauna. Our objective was to analyze the actual list of the metazoan parasites reported from CSLs and add new data on the age-related differences in the prevalence and biodiversity of the parasite community. There have been 33 species recorded but this study considers only 24 of them valid. Among them, 11 species are specific parasites of CSLs and 13 species are not specific. Additional species represent accidental infections or misidentifications. In total, 6653 helminths and 847 mites were collected and identified from 34 CSLs for this study. Six species of nematodes, . . (prevalence 41%; intensity 7.6), . . (38%; 269.6), . . (29%; 33), (9%; 2.7), (15%; 3.5) and were found. Two species of cestodes, sp. (38%; 8.5) and sp. (15%; 14.6) represent novel undescribed species. Two species of trematodes, (18%; 19.7) and (12%; 39.2), and five species of acanthocephalans, (68%; 100.8), (53%; 4.6), (3%; 1), sp. (9%; 4.3) and (6%; 8.5) were found. Mites (prevalence 85%) were found in the nasal cavity, while (21%) parasitized in the trachea and bronchi. The highest levels of infection with nematodes and trematodes were found in adult CSLs (3-16 years old), whereas the highest level of infection with acanthocephalans was found in young CSLs (pups and yearlings).
PubMed: 30228958
DOI: 10.1016/j.ijppaw.2018.09.001