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PeerJ 2016Pseudoterranovosis is a well-known human disease caused by anisakid larvae belonging to the genus Pseudoterranova. Human infection occurs after consuming infected fish....
Pseudoterranovosis is a well-known human disease caused by anisakid larvae belonging to the genus Pseudoterranova. Human infection occurs after consuming infected fish. Hence the presence of Pseudoterranova larvae in the flesh of the fish can cause serious losses and problems for the seafood, fishing and fisheries industries. The accurate identification of Pseudoterranova larvae in fish is important, but challenging because the larval stages of a number of different genera, including Pseudoterranova, Terranova and Pulchrascaris, look similar and cannot be differentiated from each other using morphological criteria, hence they are all referred to as Terranova larval type. Given that Terranova larval types in seafood are not necessarily Pseudoterranova and may not be dangerous, the aim of the present study was to investigate the occurrence of Terranova larval types in Australian marine fish and to determine their specific identity. A total of 137 fish belonging to 45 species were examined. Terranova larval types were found in 13 species, some of which were popular edible fish in Australia. The sequences of the first and second internal transcribed spacers (ITS-1 and ITS-2 respectively) of the Terranova larvae in the present study showed a high degree of similarity suggesting that they all belong to the same species. Due to the lack of a comparable sequence data of a well identified adult in the GenBank database the specific identity of Terranova larval type in the present study remains unknown. The sequence of the ITS regions of the Terranova larval type in the present study and those of Pseudoterranova spp. available in GenBank are significantly different, suggesting that larvae found in the present study do not belong to the genus Pseudoterranova, which is zoonotic. This study does not rule out the presence of Pseudoterranova larvae in Australian fish as Pseudoterranova decipiens E has been reported in adult form from seals in Antarctica and it is known that they have seasonal presence in Australian southern coasts. The genetic distinction of Terranova larval type in the present study from Pseudoterranova spp. along with the presence of more species of elasmobranchs in Australian waters (definitive hosts of Terranova spp. and Pulchrascaris spp.) than seals (definitive hosts of Pseudoterranova spp.) suggest that Terranova larval type in the present study belong to either genus Terranova or Pulchrascaris, which are not known to cause disease in humans. The present study provides essential information that could be helpful to identify Australian Terranova larval types in future studies. Examination and characterisation of further specimens, especially adults of Terranova and Pulchrascaris, is necessary to fully elucidate the identity of these larvae.
PubMed: 27014510
DOI: 10.7717/peerj.1722 -
Acta Parasitologica Dec 2015Pseudoterranova larvae parasitizing cutlassfish Trichiurus lepturus and bluefish Pomatomus saltatrix from Southwest Atlantic coast of Brazil were studied in this work by...
Pseudoterranova larvae parasitizing cutlassfish Trichiurus lepturus and bluefish Pomatomus saltatrix from Southwest Atlantic coast of Brazil were studied in this work by morphological, ultrastructural and molecular approaches. The genetic analysis were performed for the ITS2 intergenic region specific for Pseudoterranova decipiens, the partial 28S (LSU) of ribosomal DNA and the mtDNA cox-1 region. We obtained results for the 28S region and mtDNA cox-1 that was amplified using the polymerase chain reaction and sequenced to evaluate the phylogenetic relationships between sequences of this study and sequences from the GenBank. The morphological profile indicated that all the nine specimens collected from both fish were L3 larvae of Pseudoterranova sp. The genetic profile confirmed the generic level but due to the absence of similar sequences for adult parasites on GenBank for the regions amplifyied, it was not possible to identify them to the species level. The sequences obtained presented 89% of similarity with Pseudoterranova decipiens (28S sequences) and Contracaecum osculatum B (mtDNA cox-1). The low similarity allied to the fact that the amplification with the specific primer for P. decipiens didn't occur, lead us to conclude that our sequences don't belong to P. decipiens complex.
Topics: Animals; Ascaridida Infections; Ascaridoidea; Brazil; Cluster Analysis; DNA, Helminth; DNA, Mitochondrial; DNA, Ribosomal; DNA, Ribosomal Spacer; Electron Transport Complex IV; Fish Diseases; Fishes; Microscopy; Molecular Sequence Data; Phylogeny; Polymerase Chain Reaction; RNA, Ribosomal, 28S; Sequence Analysis, DNA
PubMed: 26408586
DOI: 10.1515/ap-2015-0092 -
Revista Brasileira de Parasitologia... 2015An anisakid nematode larva found in cod sold in the state of Minas Gerais, Brazil was studied by light and scanning electron microscopy and by a molecular approach....
An anisakid nematode larva found in cod sold in the state of Minas Gerais, Brazil was studied by light and scanning electron microscopy and by a molecular approach. Mitochondrial cytochrome c-oxidase subunit 2 (mtDNA cox-2), 28S rRNA and ITS1, 5.8S and ITS2 regions were amplified using the polymerase chain reaction and sequenced to evaluate the phylogenetic relationships of the larva. The genetic profile confirmed that this larva belongs to the species Pseudoterranova decipiens (sensu stricto). This is the first molecular and ultrastructural study of Pseudoterranova decipiens (sensu stricto) in imported cod sold in Brazil. The health implications of these findings are discussed.
Topics: Animals; Ascaridida Infections; Ascaridoidea; Brazil; Fish Diseases; Food Industry; Gadiformes; Larva; Microscopy, Electron, Scanning; Molecular Diagnostic Techniques
PubMed: 26154961
DOI: 10.1590/S1984-29612015037 -
Diseases of Aquatic Organisms Jun 2015A total of 190 nematodes was isolated from the stomachs of 13 beluga whales Delphinapterus leucas from the Arctic part of Hudson Bay and Hudson Strait. Infection...
A total of 190 nematodes was isolated from the stomachs of 13 beluga whales Delphinapterus leucas from the Arctic part of Hudson Bay and Hudson Strait. Infection intensity ranged from 1 to 57 specimens and prevalence was 84.62%. Morphological examination of the nematodes revealed the presence of 3 species: Pseudoterranova decipiens sensu lato, Contracaecum osculatum s.l., and Anisakis simplex s.l. Molecular analysis by PCR-based restriction fragment length polymorphism (PCR-RFLP) resulted in the identification of 4 species: Pseudoterranova bulbosa, Contracaecum osculatum A and C, and Anisakis simplex sensu stricto. The nematodes were present in 3 developmental stages: L3 (159 specimens), L4 (16 larvae), and adults (15 worms: 11 males and 4 females).
Topics: Animals; Arctic Regions; Beluga Whale; Female; Male; Nematoda; Nematode Infections; Seasons
PubMed: 26119295
DOI: 10.3354/dao02879 -
Italian Journal of Food Safety Feb 2015In this work a total of 949 fish samples were analysed for the identification of nematode larvae belonging to the Anisakidae family. Biomolecular application for the...
In this work a total of 949 fish samples were analysed for the identification of nematode larvae belonging to the Anisakidae family. Biomolecular application for the identification of Anisakidae larvae can be an optimal instrument for the traceability of fish products, described on the Reg. EC 178/2002. Results confirm a correlation between geographical distribution of fishes and presence of specific Anisakid larvae. FAO 37 zone (Mediterranean sea) showed a prevailing distribution of and a minimal presence of in hybrid form with FAO 27 zone showed a prevailing distribution of in fish like Brosme () and infestation prevalence of and in . Obtained results validate the hypothesis that molecular biology methods for identifying Anisakidae larvae are effective traceability markers of fish products.
PubMed: 27800374
DOI: 10.4081/ijfs.2015.4090 -
Emerging Infectious Diseases Feb 2015Anisakiasis in humans in South Korea has been considered to be caused exclusively by the larvae of Anisakis simplex sensu stricto and Pseudoterranova decipiens....
Anisakiasis in humans in South Korea has been considered to be caused exclusively by the larvae of Anisakis simplex sensu stricto and Pseudoterranova decipiens. Recently, however, DNA sequencing of larvae from 15 of 16 anisakiasis patients confirmed the cause to be Anisakis pegreffii infection. Molecular analysis should be performed for all extracted larvae.
Topics: Animals; Anisakiasis; Anisakis; DNA, Intergenic; Female; Humans; Male; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Republic of Korea
PubMed: 25625427
DOI: 10.3201/eid2102.140798 -
Parasites & Vectors Nov 2014Because agriculture and offshore oil extraction are significant economic activities in the southern Gulf of Mexico, high concentrations of nutrients and hydrocarbons are...
BACKGROUND
Because agriculture and offshore oil extraction are significant economic activities in the southern Gulf of Mexico, high concentrations of nutrients and hydrocarbons are expected. As parasite communities are sensitive to environmental impacts, these contaminants should have an effect on metrics such as species richness, relative abundance and similarity. Consequently, these community metrics can be used as indicators of aquatic environmental health. Our objectives were to describe the parasite communities of the shoal flounder Syacium gunteri and to determine potential thresholds above which environmental contaminants become major controlling factors of parasite community metrics.
METHODS
The study area included 33 sampling sites in the southern Gulf of Mexico, where benthic sediments, water and shoal flounder individuals were collected. Data on ecto- and endo-parasites from flounder and nutrients, contaminants and physicochemical variables from the water and sediments were obtained. The statistical associations of the parasite community metrics at the component and infracommunity levels and the environmental data were analysed using redundancy analysis (RDA).
RESULTS
Overall, 203 shoal flounder were examined for parasites, recovering 13 metazoan parasite species, and 48 physicochemical (e.g. temperature, nutrients) and contaminant (e.g. hydrocarbons, heavy metals) variables were obtained. The larval stages of the cestode Oncomegas wageneri and the nematodes Pseudoterranova decipiens and Hysterothylacium sp. were numerically dominant at the component and infracommunity levels. The parasite community metrics had significant negative statistical associations with both nitrate and total PAHs. With the exception of these two chemicals, which exceeded the threshold effect levels (TELs), no other environmental variable exceeded the range considered safe for marine organisms.
CONCLUSIONS
The community metrics chosen generally had robust statistically significant associations with both physicochemical and contaminant variables, which supports the ecological relevance of these parameters as indicators of aquatic environmental health. Within the study area, the shoal flounder and their parasites live in a polluted environment with relatively high levels of hydrocarbons and nitrate. Regarding nitrate, we emphasise that if uncontrolled sewage discharge continues in the southern Gulf of Mexico, hypoxic conditions similar to those caused by the Mississippi river can be expected in the near future.
Topics: Animals; Fish Diseases; Flounder; Gulf of Mexico; Parasitic Diseases, Animal; Prevalence; Water Pollutants, Chemical
PubMed: 25428400
DOI: 10.1186/s13071-014-0541-3 -
Parasitology Research Jan 2015The anisakid nematode Pseudoterranova decipiens, known as the sealworm or cod worm, can infect the flesh of several fish species. The parasite causes cosmetic problems...
The anisakid nematode Pseudoterranova decipiens, known as the sealworm or cod worm, can infect the flesh of several fish species. The parasite causes cosmetic problems for the fish industry and can cause abdominal discomfort if consumed by humans. There are only scattered studies on the abundance or distribution of the sealworm in fish and seals in the Baltic Sea. To remedy this situation, the extent of sealworm infection was investigated in cod (Gadus morhua) and shorthorn sculpin (Myoxocephalus scorpius) collected along the Swedish coast. A relative presence of the sealworm was also investigated in samples from grey seal (Halichoerus grypus) stomachs. Up to 100% of the fish were infected in some of the areas. Sculpin were generally worse infected than cod, both in abundance and prevalence of parasites. General linear models showed a significant correlation between the number of seals in an area and the prevalence of sealworms in cod. There was a sharp decrease of infected fish in areas with salinity lower than 7‰. Even though the northern Baltic proper and the southern Bothnian Sea have a high number of grey seals, only one sealworm was found in a sculpin in that region, and none in cod. In grey seal stomachs the sealworm was only found in samples from the central Baltic proper; further north, all anisakid nematodes identified in seals were Contracaecum osculatum. The results indicate that seal presence drives the distribution in the southern parts of the Baltic and that low salinity, or some other variable which correlates with salinity, limits the distribution in the northern part.
Topics: Animals; Ascaridida Infections; Ascaridoidea; Baltic States; Fish Diseases; Gadus morhua; Oceans and Seas; Perciformes; Seals, Earless
PubMed: 25367209
DOI: 10.1007/s00436-014-4187-z -
Veterinary Parasitology Oct 2014Baltic cod Gadus morhua (a total of total 224 specimens) captured east of the island of Bornholm in the southern Baltic Sea were subjected to a parasitological...
Baltic cod Gadus morhua (a total of total 224 specimens) captured east of the island of Bornholm in the southern Baltic Sea were subjected to a parasitological investigation between March 2013 and April 2014. Full artificial digestion of fillets from 188 cod and additional investigation of livers from 36 cod were performed. Cod or seal worm Pseudoterranova decipiens was recorded in musculature (prevalences up to 55% and intensities up to 56 worms per fish) associated with a negative correlation between worm intensity and condition factor. Liver worm Contracaecum osculatum (100% prevalence with intensities up to 320 worms per fish) in liver tissue were recorded but only a slight negative correlation between intensity and condition factor was noted. Seals act as final host for both worm species and the increased occurrence during recent years is associated with the increasing grey seal population in the area. Infection with Anisakis simplex (the herring or whale worm) in Baltic cod was found at a low level corresponding to previous studies.
Topics: Animals; Anisakiasis; Anisakis; Ascaridida Infections; Ascaridoidea; Atlantic Ocean; Base Sequence; Denmark; Fish Diseases; Gadus morhua; Sequence Analysis, DNA; Zoonoses
PubMed: 25224792
DOI: 10.1016/j.vetpar.2014.08.027 -
Parasitology Research Dec 2014Anisakid nematodes parasitize the alimentary tracts of aquatic vertebrates, including northern fur seals (Callorhinus ursinus) (NFS). The main purpose of this study was...
Anisakid nematodes parasitize the alimentary tracts of aquatic vertebrates, including northern fur seals (Callorhinus ursinus) (NFS). The main purpose of this study was to estimate the prevalence, intensity, and species composition of anisakids in NFSs on St. Paul Island, Alaska, and to analyze changes in NFS infection with these nematodes during the last decades. The study was carried out on St. Paul Island, Alaska, in July-August 2011-2013. Stomachs of 443 humanely harvested NFS males were collected from five separate haul-out areas. A total of 4,460 anisakid specimens were collected and identified by morphological criteria. Gross and histological examinations of stomachs were also performed. The overall prevalence of NFS infection was 91.2%; overall mean intensity 10.9, and overall median intensity 6. Five species, Anisakis simplex s. l., Contracaecum osculatum s. l., Pseudoterranova decipiens s. l., P. azarazi and Phocascaris cystophorae, were found. The prevalence of Anisakis was 46.5%, its intensity 7.5. The prevalence and intensity of Contracaecum, Pseudoterranova, and Phocascaris were 33.6% and 3.5, 81.9% and 6.5, and 5.2% and 1.7, respectively. Significant differences in the prevalence of NFS infection were observed between separate haul-outs. Comparison of the present data with the results of studies performed in the North Pacific in the 1960s, showed a significant decrease in the intensity of NFS infection with anisakids during the last decades. The prevalence of mucosal lesions in NFS stomachs caused by anisakids also decreased from 92 to 20.9%. Possible reasons for the changes in NFS infection with anisakids are discussed.
Topics: Alaska; Animals; Ascaridida Infections; Ascaridoidea; Fur Seals; Gastric Mucosa; Islands; Male; Prevalence
PubMed: 25216781
DOI: 10.1007/s00436-014-4131-2