Quantification of Anisakis simplex Allergens in Fresh, Long-Term Frozen, and Cooked Fish Muscle

Fish feed composition by high-throughput sequencing analysis: Parasite risk assessment

The use of wild small fish species as feed for aquaculture has clearly an economic incentive by speeding the growth of farmed species. Since feed ingredients are sourced from wild fisheries the farmed species could contain natural contaminants which may introduce food safety concerns. In this study, we used High-Throughput Sequencing (HTS) to explore the whole DNA profile of ten dry commercial feeds commonly used by Spanish fish farming companies. The feeds were mainly made of species within the genus Sprattus, Ammodytes and Clupea, and vegetables of the genus Triticum. In the feeds, DNA sequences of parasitic nematodes of fishes (˂1 % total OTUs) were also identified. A taxonomic assignment of query sequences, using a phylogeny-based approach, estimation of pairwise nucleotide identities within and between sequence groups and haplotype network analysis, allow assign short query sequences to the species Phocanema krabbei (Anisakidae) and Hysterothylacium aduncum (Rhaphidascarididae). Both species were identified as ingredient in two and six fish feeds, respectively. This result is of highly concern regarding dietetic recommendations to sensitized patients to anisakids, considering the growing evidence on the possible allergenic potential of both genera, and the recent data on the transfer of anisakid heat-resistant allergens from fishmeal to farm and aquaculture animals.

Foodborne Parasites and Their Complex Life Cycles Challenging Food Safety in Different Food Chains

Zoonotic foodborne parasites often represent complex, multi host life cycles with parasite stages in the hosts, but also in the environment. This manuscript aims to provide an overview of important zoonotic foodborne parasites, with a focus on the different food chains in which parasite stages may occur. We have chosen some examples of meat-borne parasites occurring in livestock (Taenia spp., Trichinella spp. and Toxoplasma gondii), as well as Fasciola spp., an example of a zoonotic parasite of livestock, but transmitted to humans via contaminated vegetables or water, covering the 'farm to fork' food chain; and meat-borne parasites occurring in wildlife (Trichinella spp., Toxoplasma gondii), covering the 'forest to fork' food chain. Moreover, fish-borne parasites (Clonorchis spp., Opisthorchis spp. and Anisakidae) covering the 'pond/ocean/freshwater to fork' food chain are reviewed. The increased popularity of consumption of raw and ready-to-eat meat, fish and vegetables may pose a risk for consumers, since most post-harvest processing measures do not always guarantee the complete removal of parasite stages or their effective inactivation. We also highlight the impact of increasing contact between wildlife, livestock and humans on food safety. Risk based approaches, and diagnostics and control/prevention tackled from an integrated, multipathogen and multidisciplinary point of view should be considered as well.

Prevalence and identification of Anisakis nematodes in fish consumed in Marrakesh, Morocco

Morocco is considered as an important producer of fish with more than one million tons of small pelagic fish caught per year, along more than 3400 km of coastline. Otherwise, few studies have investigated the zoonotic parasites of fish. The purpose of this study is to determine the prevalence of Anisakis nematodes larvae in two fish species, namely sardines Sardina pilchardus and mackerel Scomber scombrus. These two species are widely consumed in Marrakesh due to their availability and their affordable prices. A total of 948 fish, including 546 sardines and 402 mackerel, were purchased from the wholesale market of Marrakesh, from January 2016 to December 2018. Sampling was performed on the days of fish arrival from the fishing areas (Dakhla, Essaouira, Safi and Sidi Ifni). The samples were examined visually for the presence of Anisakis larvae. We obtained a prevalence of 8.4% in mackerel with different rates depending on their origins (Safi: 13.23%; Essaouira: 11.66%; Sidi Ifni: 2.5%; Dakhla: 0%) and the seasons. However, no larvae were detected in the sardines after meticulous visual inspection. The detected larvae were morphologically and genetically identified. We identified the larvae by the PCR-RFLP technique using the primers LSU5-F (TAGGTCGACCCGCTGAAYTTAAGCA) and IR16-R (ATTCACACCCATTGACTCGCG) from the 28S rDNA region. The analysis showed that all larvae belong to Anisakis simplex sensu-stricto (s.s.). According to our results mackerel presents a higher risk of contamination than sardine, while statistical studies show that there is no impact of season and fishing origin on the prevalence.

First report on molecular identification of Anisakis simplex in Oncorhynchus nerka from the fish market, with taxonomical issues within Anisakidae

Alive anisakids cause acute gastrointestinal diseases, and dead worms contained in food can provoke sensibilization and allergic reactions in humans. Detected in the purchased minced salmon Oncorhynchus nerka nematodes were identified as Anisakis simplex sensu stricto (Anisakidae). We found that recently published phylogenetic trees (reconstructed using different ribosomal and mitochondrial genetic markers) showed independent clusterization of species recognized in the A. simplex sensu lato species complex. This prompted us to undertake this full-fledged molecular genetics study of anisakids from Kamchatka with phylogenetic reconstructions (NJ/ML) and calculated ranges of interspecific and intergeneric p-distances using ITS1-5.8S-ITS2 sequences. We confirmed that molecular markers based on the ITS region of rDNA were able to recognize ‘pure’ specimens belonging to the cryptic species. We offer new insights into the systematics of anisakids. The genus Anisakis sensu stricto should include Anisakis simplex sensu stricto, Anisakis pegreffii, Anisakis berlandi, Anisakis ziphidarum, and Anisakis nascettii. Presumably, two genera should be restored in the structure of the subfamily Anisakinae: Skrjabinisakis for the species Anisakis paggiae, Anisakis brevispiculata, and Anisakis physeteris; and Peritrachelius for the species Anisakis typica. In addition, we provide the short annotated list of some genera of the family Anisakidae, including their diagnoses.

Intrinsic properties of anisakid nematode larvae as a potential tool for the detection in fish products

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.

Anisakis Allergy: Is Aquacultured Fish a Safe and Alternative Food to Wild-Capture Fisheries for Anisakis simplex-Sensitized Patients?

Simple Summary

The diagnosis of Anisakiasis is documented by the occasional finding of L3 larvae in the infected gastro-intestinal tract. Currently, about 14 allergens have been described, among which Ani s1 and Ani s4, both highly heat-resistant, appear central in Anisakiasis anaphylaxis and necessary to cause allergic reactions. Food has to be considered Anisakis-free only when heat-resistant Anisakis allergens are not present.

Abstract

Background: Anisakis simplex (A. simplex) infection, in humans, causes a series of clinical manifestations affecting the gastro-intestinal tract known as Anisakiasis/Anisakidosis. Patients may also present allergic manifestations such as hives and/or angioedema and even anaphylactic shock. The aim of this study was to investigate whether aquacultured fish could be considered A.simplex-free food and constitute a safe, alternative, wild-capture fish food for Gastro-Allergic Anisakiasis (GAA)-sensitized subjects. Methods: Protein extracts from A. simplex larvae in the third stage (L3) and from edible part of heavily infected horse mackerel (Trachurus trachurus) and aquacultured sea bream, have been tested for A. simplex allergens presence by immunological analysis. Western blot analysis using, as source of specific Anisakis allergens antibodies, serum samples from subjects referring allergic symptoms after raw fish ingestion, was performed. These subjects showed high levels of specific IgE anti A.simplex allergens determined by clinical laboratory tests (ISAC test). Results: Our data demonstrate the presence of Ani s4 allergen in both infected and aquacultured fish extracts, providing a possible interpretation for the allergic manifestations reported by subjects, already sensitized to A. simplex, who ate frozen or well-cooked or, even, aquacultured fish. Conclusions: The present data stimulate more accurate prophylaxis suggestions for Anisakis allergy and more specific controls of fishmeal used in aquaculture.

Estimation of the number of Anisakis larvae in commercial fish using a descriptive model based on real-time PCR

BACKGROUND

Seafood parasitation by Anisakis (Anisakidae) larvae has been reported in most of the oceans and seas worldwide. The presence of these nematodes in commonly consumed fish represents a potential hazard for consumers as they can provoke gastrointestinal symptoms and allergic reactions. In the present work, the capacity of a SYBR Green qPCR protocol to quantify Anisakis larvae in commercial fish was evaluated using experimentally spiked samples with different numbers (0-50) of A. simplex third-stage larvae (L3). To verify the agreement of the obtained results, 25 naturally infected fish specimens of Atlantic blue whiting underwent a parallel visual inspection.

RESULTS

The logarithmic behavior of the Cq data obtained from the experimentally spiked samples allowed the development of a descriptive mathematical model that correlates the Cq value with the number of Anisakis larvae (R² = 0.9908, CV = 2.37%). In the commercial blue whiting specimens there was a high correlation between the results of the molecular technique and the visual inspection (R² = 0.9912); the Bland-Altman analysis showed that 94% of the differences were within the limits of agreement (-4.98 and 6.68), indicating the reliability of the descriptive mathematical model based on the SYBR Green qPCR technique.

CONCLUSION

The descriptive function presented based on the SYBR Green qPCR assay is promising as a sensitive and accurate tool for measuring the Anisakis larval load in commercial fish, with a potential application not only in the food industry but also in prevention programs for public health. © 2020 Society of Chemical Industry.

Proteomic Insights into the Biology of the Most Important Foodborne Parasites in Europe

Foodborne parasitoses compared with bacterial and viral-caused diseases seem to be neglected, and their unrecognition is a serious issue. Parasitic diseases transmitted by food are currently becoming more common. Constantly changing eating habits, new culinary trends, and easier access to food make foodborne parasites' transmission effortless, and the increase in the diagnosis of foodborne parasitic diseases in noted worldwide. This work presents the applications of numerous proteomic methods into the studies on foodborne parasites and their possible use in targeted diagnostics. Potential directions for the future are also provided.

Development and Application of Novel Chemiluminescence Immunoassays for Highly Sensitive Detection of Anisakis simplex Proteins in Thermally Processed Seafood

The third-stage larvae (L3) of Anisakis simplex are the most important source of hidden allergens in seafood products. However, there exist no commercial methods for detecting Anisakis proteins in food. Furthermore, only a few methods have been validated for the detection of A. simplex in thermally processed food. The aims of our study are (i) the development and validation of high-sensitivity chemiluminescent (CL) immunoassays for the detection of A. simplex proteins in processed seafood, (ii) and A. simplex antigen detection in common seafood products from Polish markets. We developed and validated CL sandwich ELISA (S-ELISA) and CL competitive ELISA (C-ELISA) methods for A. simplex proteins detection in food, with respective detection limits of 0.5 and 5 ng/mL. The usefulness of the assays for detecting A. simplex proteins in highly processed food was evaluated by examination of autoclaved canned fish spiked with A. simplex larvae (1–8 larvae/200 g). Commercial real-time PCR was unable to detect A. simplex in autoclaved samples at all levels of enrichment with Anisakis larvae. CL-S-ELISA was used to test various types of seafood products from Polish markets. Among all tested products (n = 259), 28% were positive. A. simplex antigens were found mostly (n = 39) in smoked fish products: mackerel, herring, cod, and hake. Other positive samples were found in marinated herrings, canned cod livers, canned mackerels, and surimi sticks. In tuna, Atlantic argentine, anchovy, sardine, sprat, and squid products, A. simplex antigens were not detected. This study provides novel effective tools for the detection of A. simplex proteins in processed food and highlights the potential allergic hazards for Anisakis-sensitized Polish consumers of seafood.

Investigation of Anisakis larvae in different products of ready-to-eat fish meat and imported frozen fish in Turkey

Globalization opens new market areas and affects food consumption habits, resulting in rapid and remarkable cultural change. Food habits such as consumption of raw fish meat have become popular, resulting in increased risk of emerging infectious diseases. Anisakis simplex sensu stricto (s.s) and A. pegreffii are the most common and important fish-borne zoonotic nematodes responsible for human anisakiasis, which occurs through the consumption of raw or undercooked fish as well as cooked fish due to their heat-stable allergens. Here, we investigated the prevalence, intensity, and abundance of Anisakis larvae in imported fish and ready-to-eat local fish products in Turkey. A total of 205 ready-to-eat fish products, 100 imported frozen Atlantic salmon (Salmo salar) fillets, and 100 imported frozen whole Atlantic mackerel (Scomber scombrus) were sampled from supermarkets, sushi restaurants, and fish markets. All samples were individually examined using a pepsin digestion technique. In total, 602 Anisakis type I larvae were recovered from 98/100 mackerel. No larvae were found in ready-to-eat products or frozen Atlantic salmon fillets. Overall, 8.8% of the larvae were found in the muscle tissue. The overall mean intensity and abundance of infection in mackerel were 6.14 and 6.02, respectively. The larvae were molecularly identified and their phylogenetic relationships with the relevant Anisakis sequences in GenBank were investigated. For this purpose, a subsample of randomly selected 100 Anisakis larvae were analyzed with PCR-RFLP of the ITS region. The larvae were identified as A. simplex (s.s.) (n = 87) and hybrids (n = 13). ITS and cox2 gene regions of all hybrids and randomly selected 50 A. simplex (s.s.) larvae were sequenced for species confirmation and phylogenetic analyses. No intraspecific nucleotide variation was found among the ITS sequences of either species. Seven and three haplotypes, respectively, were identified for A. simplex (s.s.) and hybrid species according to DNA polymorphism of the cox2 gene. Hybrids in our study clustered within the common A. simplex (s.s.) clade in the cox2 phylogenetic tree indicating the dominance of A. simplex (s.s) in the catching area of Atlantic mackerel. Consequently, our study indicates high occurrence of A. simplex (s.s.) larvae with an overall 98.0% prevalence in imported Atlantic mackerel, and highlights the importance of these fish as potential reservoirs for human allergic anisakiasis in Turkey and possibly in other countries.

Proteomic and Bioinformatic Investigations of Heat-Treated Anisakis simplex Third-Stage Larvae

Anisakis simplex third-stage larvae are the main source of hidden allergens in marine fish products. Some Anisakis allergens are thermostable and, even highly processed, could cause hypersensitivity reactions. However, Anisakis proteome has not been studied under autoclaving conditions of 121 °C for 60 min, which is an important process in the food industry. The aim of the study was the identification and characterization of allergens, potential allergens, and other proteins of heat-treated A. simplex larvae. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to identify 470 proteins, including allergens-Ani s 1, Ani s 2, Ani s 3, Ani s 4, Ani s 5-and 13 potential allergens that were mainly homologs of Anisakis spp., Ascaris spp., and Acari allergens. Ani s 2, Ani s 3, Ani s 5, and three possible allergens were found among the top 25 most abundant proteins. The computational analysis allowed us to detect allergen epitopes, assign protein families, and domains as well as to annotate the localization of proteins. The predicted 3D models of proteins revealed similarities between potential allergens and homologous allergens. Despite the partial degradation of heated A. simplex antigens, their immunoreactivity with anti-A. simplex IgG antibodies was confirmed using a Western blot. In conclusion, identified epitopes of allergenic peptides highlighted that the occurrence of Anisakis proteins in thermally processed fish products could be a potential allergic hazard. Further studies are necessary to confirm the IgE immunoreactivity and thermostability of identified proteins.

First Molecular Diagnosis of Clinical Cases of Gastric Anisakiosis in Spain

Anisakiosis is a fish-borne disease with gastrointestinal and/or allergic symptoms caused by the consumption of raw or undercooked fish parasitized with nematode larvae of the genus Anisakis. In Europe, Anisakis pegreffii has been detected as the causative agent, although the sibling species Anisakis simplex sensu stricto (s.s.) is also known to cause the disease in other parts of the world, and discrepancies exist regarding their respective pathogenic potential. In Spain a high number of cases has been recorded, with marinated anchovies being the main source of infection, although no specific diagnosis has been documented in humans. In this study, we analyzed three cases of anisakiosis in patients from Barcelona (Spain) who had consumed undercooked hake. All patients described epigastric pain and several larval nematodes were removed endoscopically from their stomachs. Larvae were morphologically characterized as third-stage larvae of Anisakis simplex sensu lato (s.l.) and molecularly identified as A. simplex (s.s.) by means of PCR RFLP of the ITS region of the rDNA and sequencing of the elongation factor1 alpha1 (EF1 α-1) nDNA gen. This study represents the first specific identification of Anisakis larvae in clinical cases of anisakiosis reported in Spain. Specific molecular diagnosis is of crucial importance for assessing the health risk of Anisakis sibling species. Hake consumption stands out as a risk factor for anisakiosis, since this fish species can be highly parasitized.

Validation of a Commercial Loop-Mediated Isothermal Amplification (LAMP) Assay for the Rapid Detection of Anisakis spp. DNA in Processed Fish Products

Parasites belonging to the Anisakis genera are organisms of interest for human health because they are responsible for the Anisakiasis zoonosis, caused by the ingestion of raw or undercooked fish. Furthermore, several authors have reported this parasite to be a relevant inducer of acute or chronic allergic diseases. In this work, a rapid commercial system based on Loop-Mediated Isothermal Amplification (LAMP) was optimised and validated for the sensitive and rapid detection of Anisakis spp. DNA in processed fish products. The specificity and sensitivity of the LAMP assay for processed fish samples experimentally infected with Anisakis spp. larvae and DNA were determined. The LAMP system proposed in this study was able to give positive amplification for all the processed fish samples artificially contaminated with Anisakis spp., giving sensitivity values equal to 100%. Specificity tests provided no amplification for the Contracaecum, Pseudoterranova, or Hysterothylacium genera and uninfected samples. The limit of detection (LOD) of the LAMP assay proposed was 10² times lower than the real-time PCR method compared. To the best of our knowledge, this is the first report regarding the application of the LAMP assay for the detection of Anisakis spp. in processed fish products. The results obtained indicate that the LAMP assay validated in this work could be a reliable, easy-to-use, and convenient tool for the rapid detection of Anisakis DNA in fish product inspection.

A parasitological evaluation of edible insects and their role in the transmission of parasitic diseases to humans and animals

From 1 January 2018 came into force Regulation (EU) 2015/2238 of the European Parliament and of the Council of 25 November 2015, introducing the concept of "novel foods", including insects and their parts. One of the most commonly used species of insects are: mealworms (Tenebrio molitor), house crickets (Acheta domesticus), cockroaches (Blattodea) and migratory locusts (Locusta migrans). In this context, the unfathomable issue is the role of edible insects in transmitting parasitic diseases that can cause significant losses in their breeding and may pose a threat to humans and animals. The aim of this study was to identify and evaluate the developmental forms of parasites colonizing edible insects in household farms and pet stores in Central Europe and to determine the potential risk of parasitic infections for humans and animals. The experimental material comprised samples of live insects (imagines) from 300 household farms and pet stores, including 75 mealworm farms, 75 house cricket farms, 75 Madagascar hissing cockroach farms and 75 migrating locust farms. Parasites were detected in 244 (81.33%) out of 300 (100%) examined insect farms. In 206 (68.67%) of the cases, the identified parasites were pathogenic for insects only; in 106 (35.33%) cases, parasites were potentially parasitic for animals; and in 91 (30.33%) cases, parasites were potentially pathogenic for humans. Edible insects are an underestimated reservoir of human and animal parasites. Our research indicates the important role of these insects in the epidemiology of parasites pathogenic to vertebrates. Conducted parasitological examination suggests that edible insects may be the most important parasite vector for domestic insectivorous animals. According to our studies the future research should focus on the need for constant monitoring of studied insect farms for pathogens, thus increasing food and feed safety.

Exposure to Anisakis extracts can induce inflammation on in vitro cultured human colonic cells

Anisakis spp. is a parasitic nematode whose infective third-stage larvae may be found within the flesh of fish species commonly consumed by humans. Thorough cooking or freezing should render the fish safe for consumption; furthermore, marinating solutions containing biocidal agents might have a significant action against Anisakis larvae. Some studies suggest a relationship between some parasitic infections and development of inflammatory bowel disorders, and Anisakis infection might be a risk factor for stomach or colon cancer. The aim of our study was to investigate if crude extracts (CEs) obtained from Anisakis larvae marinated in a solution with added allyl isothiocyanate (ACE-AITC) and frozen, or from frozen only Anisakis larvae (ACE), can induce an inflammatory effect on in vitro differentiated colonic Caco-2 cells exposed or not to LPS. Caco-2 exposure to the two CEs induced a marked COX-2 expression and potentiated LPS-induced COX-2 overexpression, confirming that substances present in Anisakis larvae can induce an inflammatory response in the intestinal epithelium, possibly also exacerbating the effects of other inflammatory stimuli. ACE induced a marked decrease in caspase-3 activation, while AITC-ACE increased its activation. However, LPS-induced caspase-3 activation appeared lower in cells treated with ACE and with the lower concentration of AITC-ACE. Thus, it is evident that Anisakis CEs may affect various cell pathways crucial not only in the inflammatory process but also in cell growth and death. Thus, CEs obtained from nonviable Anisakis larvae retain or are otherwise provided with noxious properties able to induce a strong inflammation response in intestinal epithelial cells. Furthermore, their influence may persist also following pretreatment with the biocidal agent AITC, indicating that the harmful substances contained in crude extracts from Anisakis larvae are resistant to the thermal or biocidal agent treatments.

Changes over Time in IgE Sensitization to Allergens of the Fish Parasite Anisakis spp

BACKGROUND

Sensitization to Anisakis spp. can produce allergic reactions after eating raw or undercooked parasitized fish. Specific IgE is detected long after the onset of symptoms, but the changes in specific IgE levels over a long follow-up period are unknown; furthermore, the influence of Anisakis spp. allergen exposure through consumption of fishery products is also unknown.

OBJECTIVE

To analyse the changes in IgE sensitization to Anisakis spp. allergens over several years of follow-up and the influence of the consumption of fishery products in IgE sensitization.

METHODS

Total IgE, Anisakis spp.-specific IgE, anti-Ani s 1 and anti-Ani s 4 IgE were repeatedly measured over a median follow-up duration of 49 months in 17 sensitized patients.

RESULTS

Anisakis spp.-specific IgE was detected in 16/17 patients throughout the follow-up period. The comparison between baseline and last visit measurements showed significant decreases in both total IgE and specific IgE. The specific IgE values had an exponential or polynomial decay trend in 13/17 patients. In 4/17 patients, an increase in specific IgE level with the introduction of fish to the diet was observed. Three patients reported symptoms after eating aquaculture or previously frozen fish, and in two of those patients, symptom presentation was coincident with an increase in specific IgE level.

CONCLUSIONS

IgE sensitization to Anisakis spp. allergens lasts for many years since specific IgE was detectable in some patients after more than 8 years from the allergic episode. Specific IgE monitoring showed that specific IgE titres increase in some allergic patients and that allergen contamination of fishery products can account for the observed increase in Anisakis spp.-specific IgE level.

CLINICAL RELEVANCE

Following sensitization to Anisakis spp. allergens, the absence of additional exposure to those allergens does not result in the loss of IgE sensitization. Exposure to Anisakis spp. allergens in fishery products can increase the specific IgE level in some sensitized patients.

High prevalence of Anisakis simplex hypersensitivity and allergy in Sicily, Italy

BACKGROUND

Anisakis simplex can elicit allergic reactions when ingested in raw or marinated fish. The prevalence of A simplex hypersensitivity and allergy in Sicily (Italy), an area where the consumption of raw or marinated fish is very common, has not been investigated thus far.

OBJECTIVE

To investigate the prevalence of A simplex sensitization and its clinical relevance in a large group of unselected patients.

METHODS

All consecutive patients referred to the authors' allergy clinic during a 22 month-period were included in the study, evaluated for sensitization to A simplex and other allergens depending on their clinical history, and investigated for allergic symptoms after the ingestion of raw or marinated fish.

RESULTS

Of 3,419 patients screened, 527 (15.4%) were sensitized to A simplex and 29 of these (5.5% of sensitized patients) had a history of A simplex allergy. Approximately 30% of patients had mono-sensitization to A simplex. Co-sensitization to house dust mites or molds yielded an odds ratio of 1.98 or 3.18, respectively, for allergy to A simplex.

CONCLUSION

A high prevalence of A simplex sensitization in a large proportion of patients with mono-sensitization was found, confirming that eating habits influence sensitization to this nematode. Allergic symptoms from A simplex ingestion in raw or marinated fish were quite frequent, with symptoms ranging from oral allergy syndrome to anaphylaxis. Patients sensitized to A simplex were more prone to have allergic symptoms when they had co-sensitization to house dust mites or molds, suggesting possible cross-reactive but clinically relevant allergens between these allergenic sources.

MOLECULAR IDENTIFICATION OF Pseudoterranova azarasi LARVAE IN COD (Gadus sp.) SOLD FOR HUMAN CONSUMPTION IN BRAZIL

Anisakiasis and Pseudoterranovosis are human diseases caused by the ingestion of live Anisakidae larvae in raw, undercooked or lightly marinated fish. Larvae were collected from one salted cod sold for human consumption in a Sao Paulo market in 2013. One section of one brownish larva was used for molecular analyses. The partial COX2 gene sequence from the larva had a nucleotide identity of 99.8 % with Pseudoterranova azarasi, which belongs to the Pseudoterranova decipiens species complex. The risk of allergy when consuming dead larvae in salted fish is not well known and should be considered.

Development of liquid chromatography-tandem mass spectrometry methods for the quantitation of Anisakis simplex proteins in fish

The parasite Anisakis simplex is present in many marine fish species that are directly used as food or in processed products. The anisakid larvae infect mostly the gut and inner organs of fish but have also been shown to penetrate into the fillet. Thus, human health can be at risk, either by contracting anisakiasis through the consumption of raw or under-cooked fish, or by sensitisation to anisakid proteins in processed food. A number of different methods for the detection of A. simplex in fish and products thereof have been developed, including visual techniques and PCR for larvae tracing, and immunological assays for the determination of proteins. The recent identification of a number of anisakid proteins by mass spectrometry-based proteomics has laid the groundwork for the development of two quantitative liquid chromatography-tandem mass spectrometry methods for the detection of A. simplex in fish that are described in the present study. Both, the label-free semi-quantitative nLC-nESI-Orbitrap-MS/MS (MS1) and the heavy peptide-applying absolute-quantitative (AQUA) LC-TripleQ-MS/MS (MS2) use unique reporter peptides derived from anisakid hemoglobin and SXP/RAL-2 protein as analytes. Standard curves in buffer and in salmon matrix showed limits of detection at 1μg/mL and 10μg/mL for MS1 and 0.1μg/mL and 2μg/mL for MS2. Preliminary method validation included the assessment of sensitivity, repeatability, reproducibility, and applicability to incurred and naturally-contaminated samples for both assays. By further optimization and full validation in accordance with current recommendations the LC-MS/MS methods could be standardized and used generally as confirmative techniques for the detection of A. simplex protein in fish.

Removal of Anisakis simplex allergens from infected fish during the washing step of surimi production

BACKGOUND

The washing operation of fish muscle is one of the key steps in the production of surimi. The aim of this study was to assess in parasitised minced fish the effect of the washing steps on the allergen removal of Anisakis simplex and on protein yield during surimi processing. Experimentally infected hake (Merluccius merluccius) (50 Anisakis simplex s.s L3 larvae per 100 g of muscle) underwent three successive washing steps with water, phosphate buffer (20 mmol L(-1) ), sodium bicarbonate (60 mmol L(-1) ), or sodium hypochlorite (0.27 mmol L(-1) ) in the surimi processing (4 kg muscle, 1:4 w/v for each solution). Total protein concentration and A. simplex antigens and allergens were evaluated in each waste fraction.

RESULTS

The highest removal of Ani s 4 and A. simplex antigens was achieved by using phosphate buffer, together with a good protein yield in the raw surimi. Decrease of the concentration of allergens and antigens as a function of the washing steps rendered a linear trend (R(2) = 0.95 and 0.98 for Ani s 4 and A. simplex antigens, respectively).

CONCLUSION

The conditions for an optimal removal of Anisakis allergens can be established and calculated as a function of the washing steps. This approach opens a line to utilise parasitised fish in a safer way. © 2014 Society of Chemical Industry.

Antigenicity of Anisakis simplex s.s. L3 in parasitized fish after heating conditions used in the canning processing

BACKGROUND

Some technological and food processing treatments applied to parasitized fish kill the Anisakis larvae and prevent infection and sensitization of consumers. However, residual allergenic activity of parasite allergens has been shown. The aim here was to study the effect of different heat treatments used in the fish canning processing industry on the antigen recognition of Anisakis L3. Bigeye tuna (Thunnus obesus) and yellowfin tuna (Thunnus albacares) were experimentally infected with live L3 Anisakis. After 48 h at 5 ± 1 °C, brine was added to the muscle, which was then canned raw (live larvae) or heated (90 °C, 30 min) (dead larvae) and treated at 113 °C for 60 min or at 115 °C for 90 min. Anisakis antigens and Ani s 4 were detected with anti-crude extract and anti-Ani s 4 antisera respectively.

RESULTS

Ani s 4 decreased in all lots, but the muscle retained part of the allergenicity irrespective of the canning method, as observed by immunohistochemistry. Dot blot analysis showed a high loss of Ani s 4 recognition after canning, but residual antigenicity was present.

CONCLUSION

The results indicate that heat treatment for sterilization under the conditions studied produces a decrease in Ani s 4 and suggest a potential exposure risk for Anisakis-sensitized patients.

Identification of autoclave-resistant Anisakis simplex allergens

Anisakis simplex is a fish parasite able to induce allergic reactions in humans infected when eating raw or undercooked fish parasitized with viable third-stage larvae. Some authors claim that exposure to nonviable Anisakis material can result in allergic symptoms in previously sensitized patients, indicating that parasite allergens are resistant to the thermal treatments of usual cooking procedures. Furthermore, some patients report symptoms after eating canned fish. The aim of this work was the analysis of parasite allergen stability in heating to 121 °C in an autoclave to simulate the thermal process applied to canned fish. Third-stage larvae were subjected to autoclaving for 20, 40, and 80 min, and parasite crude extracts were analyzed by electrophoresis, immunoblotting, and a flow-cytometric basophil activation test. Allergens resistant to autoclaving were separated by reversed-phase high-performance liquid chromatography and identified by ion trap mass spectrometry. Protein analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that autoclaving considerably reduced the number and intensity of identifiable protein bands in a time-dependent manner. Several allergens were detected by immunoblotting with a pool of A. simplex allergic patients' sera after autoclaving. Allergens of 9 and 14 kDa resistant to autoclaving were identified as Ani s 4 and Ani s 1 allergens, respectively. Functional analysis showed that allergens retain their capacity to activate basophils even after autoclaving for 80 min. In conclusion, some relevant A. simplex allergens retain their capacity to bind immunoglobulin E and activate basophils after being subjected to autoclaving, which is a method equivalent to that used in industrial canning processes.

Foodborne anisakiasis and allergy

Human anisakiasis, a disease caused by Anisakis spp. (Nematoda), is often associated with clinical signs that are similar to those associated with bacterial or viral gastroenteritis. With the globalisation of the seafood industry, the risk of humans acquiring anisakiasis in developed countries appears to be underestimated. The importance of this disease is not only in its initial manifestation, which can often become chronic if the immune response does not eliminate the worm, but, importantly, in its subsequent sensitisation of the human patient. This sensitisation to Anisakis-derived allergens can put the patient at risk of an allergic exacerbation upon secondary exposure. This article reviews some aspects of this food-borne disease and explains its link to chronic, allergic conditions in humans.

A scoring system approach for the parasite predictive assessment of fish lots: a proof of concept with anisakids

A total of 982 individuals distributed in 11 lots belonging to 10 fish species from three Atlantic FAO fishing areas were sampled and examined to detect the presence of anisakid larvae in fish muscle. After hazard identification by genetic sequencing and exposure assessment by anatomic extent and demographic characterization of infection, all data were fitted for each fish species to a new proposed scoring schema of parasite prediction. In the absence of a criterion standard method for inspection and precise definition of the quantum satis for parasites in contaminated fish lots, the inspection rating scheme called SADE (Site of infection, Assurance of quality, Demography, Epidemiology) may help fish industries to precisely handle and to evaluate the likely outcome of infected fish lots after being diagnosed. For this purpose, a supporting flow diagram for decision was defined and suggested. This new performance assessment tool has the aim of staging fish lots, thus helping in planning manufacture, commercial, and research decisions during self-management programs. This novel scoring system provides an improved inspection format by implementing the occurrence stratification for parasites to guide Hazard Analysis and Critical Control Points (HACCP) programs for the uniform exchange of information among fish industries, administration and researchers, thus facilitating standardization and communication. In the future, this scoring version could be validated (in terms of classification and wording) for similar overall predictive purposes in other muscular parasites infecting seafood products.

Granulocytes in helminth infection -- who is calling the shots?

Helminths are parasitic organisms that can be broadly described as “worms” due to their elongated body plan, but which otherwise differ in shape, development, migratory routes and the predilection site of the adults and larvae. They are divided into three major groups: trematodes (flukes), which are leaf-shaped, hermaphroditic (except for blood flukes) flatworms with oral and ventral suckers; cestodes (tapeworms), which are segmented, hermaphroditic flatworms that inhabit the intestinal lumen; and nematodes (roundworms), which are dioecious, cylindrical parasites that inhabit intestinal and peripheral tissue sites. Helminths exhibit a sublime co-evolution with the host´s immune system that has enabled them to successfully colonize almost all multicellular species present in every geographical environment, including over two billion humans. In the face of this challenge, the host immune system has evolved to strike a delicate balance between attempts to neutralize the infectious assault versus limitation of damage to host tissues. Among the most important cell types during helminthic invasion are granulocytes: eosinophils, neutrophils and basophils. Depending on the specific context, these leukocytes may have pivotal roles in host protection, immunopathology, or facilitation of helminth establishment. This review provides an overview of the function of granulocytes in helminthic infections.