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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 -
International Journal of Food... Aug 2020Anisakidae and Raphidascaridae are marine nematodes present in a wide range of fish hosts, which may cause gastro-intestinal complaints and/or allergy in human, in...
Anisakidae and Raphidascaridae are marine nematodes present in a wide range of fish hosts, which may cause gastro-intestinal complaints and/or allergy in human, in addition to economic losses for the industry. Data regarding the presence of these parasites in fish for the Belgian market is currently missing; therefore, our aim was to investigate the presence and intensity of ascaridoids in a wide range of commercially fish species. A total of 415 fish samples, belonging to 36 different fish species, were collected from a Belgian whole-sale company. Ascaridoid larvae from the viscera (if present) and the muscles were collected by enzymatic digestion and the prevalence, median intensity, mean number of larvae per 100 g infected muscle, and localisation were determined. An overall prevalence of 53% [95%-CI: 42-63%] in the viscera and 27% [95%-CI: 23-32%] in the muscles was observed. Infection in the muscles varied between the fish species; no larvae were detected in 13 fish species, while a high prevalence (>78%) was observed in pollack, halibut, and gurnard. Most samples originated from the Northeast Atlantic Ocean, with the highest prevalence in the muscles observed in the Barents & Norwegian Sea (65% [95%-CI: 38-86]). Muscle samples were, if possible, divided in an anterior region, belly flap, medial region, and posterior region, with the most infections and larvae found in the belly flaps. In all samples, a total of 2569 larvae were recovered, with 1594 larvae originating from the viscera and 975 from the muscles; with an average of two larvae per 100 g infected fillet detected. Larvae were morphologically identified, and a subgroup was further confirmed using PCR/RFLP, resulting ultimately in the identification of Anisakis simplex s.s. (1853 larvae), A. pegreffii (137), A. simplex/pegreffii hybrid genotype (38), Pseudoterranova decipiens (160) and Hysterothylacium aduncum (380). This study demonstrates that ascaridoid larvae are highly prevalent in different fish species on the Belgian market.
Topics: Animals; Anisakiasis; Anisakis; Ascaridida Infections; Ascaridoidea; Atlantic Ocean; Belgium; Fish Diseases; Fishes; Food Parasitology; Humans; Larva; Muscles; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Seafood
PubMed: 32422589
DOI: 10.1016/j.ijfoodmicro.2020.108657 -
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