RESUMEN

Anisakiasis is a food-borne parasitic disease mainly caused by the third stage of Anisakis simplex (s. s.) and Anisakis pegreffii. Traditional methods for detecting of Anisakis involve morphology identification such as visual inspection, enzyme digestion, and molecular methods based on PCR, but they have certain limitations. In this study, the internal transcribed spacer 1 (ITS 1) regions of Anisakis were targeted to develop a visual screening method for detecting A. simplex (s. s.) and A. pegreffii in fish meat based on recombinase polymerase amplification (RPA) combined with lateral flow dipstick (LFD). Specific primers and probes were designed and optimized for temperature, reaction time, and detection threshold. LFD produced clear visual results that were easily identifiable after a consistent incubation of 10-20 min at 37 °C. The whole process of DNA amplification by RPA and readout by LFD did not exceed 30 min. In addition, the detection limit is up to 9.5 × 10-4 ng/µL, and the detection of the artificially contaminated samples showed that the developed assay can effectively and specifically detect A. simplex (s. s.) and A. pegreffii, which fully meet the market's requirements for fish food safety supervision.

RESUMEN

We report on an optimization study of percussion drilling thin metal sheets employing a high repetition rate, high power femtosecond laser with respect to the resulting heat accumulation. A specified simplex algorithm was employed to optimize the spatial drilling sequence, whereas a simplified thermal simulation using COMSOL was validated by comparing its results to the temperature measurements using an infrared camera. Optimization for drilling borehole matrices was aspired with respect to the generated temperature across the processed specimen, while the drilling strategy was altered in its spatial drilling sequence and by using multi-spot approaches generated by a spatial light modulator. As a result, we found that an optimization strategy based on limited consecutive holes in a Moore neighborhood led to reduced temperatures and the shortest process times.

RESUMEN

Anisakidosis is a zoonotic infection caused by members of the family Anisakidae. The presence of anisakid larvae in fish poses risk for humans and dissuade consumers from purchasing infected products. Although fish constitute important component of Egyptian diet, the prevalence of anisakid larvae in marketed fish in Egypt is not well described. Furthermore, the species of anisakid larvae is not defined in most of the available studies due to the over reliance on morphological analyses. The aim of the current work was to assess the prevalence and intensity of anisakid larvae in three common marketed fish in Egypt (Atlantic herring, Mediterranean horse mackerel and Atlantic mackerel) and to determine the species of the isolated larvae using morphological and molecular methods. Light and scanning electron microscope (SEM) analyses revealed the details of the isolated larvae. However, partial sequencing of cytochrome oxidase subunite-1 (mt cox1) gene revealed that all larvae isolated from Atlantic herring and Mediterranean horse mackerel belonged to Anisakis simplex sensu stricto with prevalence of 87.1% and 83.3%, respectively, whereas Atlantic mackerel harbored Anisakis typica with a prevalence of 42.8%. The Mediterranean horse mackerel demonstrated the highest larval mean intensity (n = 20 larvae/infected fish). This study highlights the importance of these fish as potential reservoirs for human anisakiasis in Egypt and possibly in other coastal countries.

RESUMEN

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.

Asunto(s)

RESUMEN

A multi-marker nuclear genotyping approach was performed on larval and adult specimens of Anisakis spp. (N = 689) collected from fish and cetaceans in allopatric and sympatric areas of the two species Anisakis pegreffii and Anisakis simplex (s. s.), in order to: (1) identify specimens belonging to the parental taxa by using nuclear markers (allozymes loci) and sequence analysis of a new diagnostic nuclear DNA locus (i.e. partial sequence of the EF1 α-1 nDNA region) and (2) recognize hybrid categories. According to the Bayesian clustering algorithms, based on those markers, most of the individuals (N = 678) were identified as the parental species [i.e. A. pegreffii or A. simplex (s. s.)], whereas a smaller portion (N = 11) were recognized as F1 hybrids. Discordant results were obtained when using the polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLPs) of the internal transcribed spacer (ITS) ribosomal DNA (rDNA) on the same specimens, which indicated the occurrence of a large number of 'hybrids' both in sympatry and allopatry. These findings raise the question of possible misidentification of specimens belonging to the two parental Anisakis and their hybrid categories derived from the application of that single marker (i.e. PCR-RFLPs analysis of the ITS of rDNA). Finally, Bayesian clustering, using allozymes and EF1 α-1 nDNA markers, has demonstrated that hybridization between A. pegreffii and A. simplex (s. s.) is a contemporary phenomenon in sympatric areas, while no introgressive hybridization takes place between the two species.

Asunto(s)

RESUMEN

Seafood allergies have been increasing their presence in the last 2 decades. Allergic reactions to seafood can range from mild urticarial and oral allergy syndrome to life-threatening anaphylactic reactions. Ingestion of seafood infested with Anisakis larvae can cause a disease known as anisakiasis with symptoms similar to true seafood allergy. Furthermore, some adverse reactions to seafood including histamine fish poisoning (HFP), and intolerance to histamine can trigger clinical symptoms, which, although nonallergic in origin, are similar to true immunoglobulin E (IgE)-mediated allergic reactions. Because seafood allergy usually remains a lifelong food allergy, this review focuses on the current knowledge on fish and shellfish allergens and emphasizes the importance of differentiating seafood allergy from other allergy-like reactions (anisakiasis, HFP, and intolerance to histamine). Key teaching points: • Fish and shellfish are potent allergens that can provoke serious IgE antibody-mediated adverse reactions in sensitive individuals. • Sensitization to seafood allergens can be achieved by ingestion, inhalation, or skin contact. • Shellfish major allergen, tropomyosin, shares significant homology to arthropods (dust mites and cockroaches). • Accidental exposures to seafood products cross-contaminated with fish or shellfish allergens (hidden allergens) during processing may present a health risk for sensitive individuals. • Allergens of fish parasite A. simplex present common hidden allergens in seafood, particularly in raw and undercooked home-made fish dishes. • Symptoms caused by HFP, histamine intolerance, and anisakiasis are similar to true seafood allergy.

Asunto(s)

RESUMEN

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.

Asunto(s)

RESUMEN

It remains unclear whether allergens are the same among the sibling species of Anisakis simplex sensu lato. This study was carried out to compare the amino acid sequences of three major (Ani s 1, 2 and 12) and one minor (Ani s 9) Anisakis allergens between A. simplex s.s. and Anisakis pegreffii. We found 2 (out of 163), 1 (out of 869), and 29 (out of 266) amino acid variable sites for Ani s 1, 2, and 12, respectively. However, as both intra- and inter-species variations were present at the same amino acid positions, no amino acid variations clearly distinguished the two sibling species. IgE-binding epitopes (Ani s 1) and a binding motif of human leukocyte antigen (Ani s 2 and 9) demonstrated by previous studies were conserved. The similarities of the amino acid sequences of the allergens indicate possible similar allergy-associated health risks in humans infected with or accidentally ingesting either Anisakis species.

Asunto(s)