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.

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.

Six new species of Cichlidogyrus Paperna, 1960 (Platyhelminthes: Monogenea) from the gills of cichlids (Teleostei: Cichliformes) from the Lomami River Basin (DRC: Middle Congo).

BACKGROUND: Monogenea van Beneden, 1858 is a group of parasitic flatworms, commonly found infecting bony fish. Several genera, such as Cichlidogyrus Paperna, 1960, are reported to include potential pathogenic species that can negatively impact aquaculture fish stocks. They can switch from introduced to native fish and vice versa. In Africa (and all over the world), fish species belonging to Cichlidae are often kept in aquaculture and represent a major source of food. Thus, research on the biodiversity and occurrence of monogenean species on these fish is of importance for aquaculture and conservation. The present study is a survey of the diversity of species of Cichlidogyrus in the south of the Democratic Republic of the Congo (DRC) on three cichlid species: Orthochromis sp. 'Lomami', Serranochromis cf. macrocephalus, and Tilapia sparrmanii Smith, 1840. METHODS: Specimens of Cichlidogyrus were isolated from the gills and mounted on glass slides with Hoyer's medium. The genital and haptoral hard parts were measured and drawn using interference contrast. RESULTS: In total, six species of Cichlidogyrus were found, all new to science: C. bulbophallus n. sp. and C. pseudozambezensis n. sp. on S. cf. macrocephalus, C. flagellum n. sp. and C. lobus n. sp. on T. sparrmanii, C. ranula n. sp. on S. cf. macrocephalus and Orthochromis sp. 'Lomami', and C. maeander n. sp. found on Orthochromis sp. 'Lomami' and T. sparrmanii. The first four species are considered to be strict specialists, C. ranula n. sp. an intermediate generalist and C. maeander n. sp. a generalist. These parasite species show morphological similarities to species found in the Lower Guinea and Zambezi ichthyofaunal provinces, which might be explained by past river capture events between river systems of the Congo Province and both these regions. CONCLUSIONS: Serranochromis cf. macrocephalus and Orthochromis sp. 'Lomami' can harbour respectively three and two species of Cichlidogyrus, all described in this study. Tilapia sparrmanii can harbour seven species, of which three are described in the present study. These results highlight the species diversity of this parasite genus in the Congo Basin.

Risk-based scoring and genetic identification for anisakids in frozen fish products from Atlantic FAO areas.

BACKGROUND: The presence of Anisakis larvae in fish represents a major public health concern. Effective risk management procedures should be applied to prevent heavily infected products from reaching the market. The aim of the study is to provide preliminary data on parasite exposure and risk classification in frozen fish products by applying a risk categorization scheme (site, abundance, density and epidemiology - SADE) and Fish Parasite Rating (FPR) method. Fish and cephalopods samples (N = 771) from 5 different FAO Atlantic areas were examined and categorized after an accurate visual inspection and a chloro-peptic digestion. RESULTS: In 25 out of 33 fish species parasite larvae were found. 10897 anisakids larvae were collected and identified to genus level. Molva dypterygia, Conger conger, Zeus faber and Aphanopus carbo were shown to be the most highly infected species. SADE and FPR scores were 1 and poor, respectively, for the referred species, because of the disseminated Anisakis infection and commercial rejection. CONCLUSION: SADE/FPR method showed high specificity and accuracy. The information provided in this work could be used in early warning systems for the detection of parasites in fishery products and might help fishing industries in establishing management strategies for infected stocks in terms of cost saving decisions.

Digenean Holostephanus (Trematoda: Digenea: Cyathocotylidae) metacercariae in common carp (Cyprinus carpio Linnaeus, 1758) muscle: zoonotic potential and sensitivity to physico-chemical treatments.

Metacercariae of various species within the genus Holostephanus Szidat, 1936 (Trematoda: Digenea: Cyathocotylidae) occur in muscles of both farmed and wild fish, including common carp (Cyprinus carpio Linnaeus, 1758). The life cycle includes a snail as first intermediate host, fish as second intermediate host and birds or mammals as final hosts. We studied the zoonotic potential and the viability of Holostephanus metacercariae from common carp following exposure to various physical and chemical treatments. Muscle tissue samples of common carp specimens from a fish farm in the north-eastern part of Hungary were examined and metacercariae recovered. The zoonotic potential was evaluated experimentally by using small mammals as models (albino mice, n = 2; and Syrian hamsters, n = 4) infected per os with Holostephanus cysts. Parallelly, Metagonimus metacercariae were used as positive controls. We could not confirm the zoonotic potential of Holostephanus metacercariae as they did not survive in the mammalian intestine whereas Metagonimus metacercariae developed to the adult stage. We assessed the viability of metacercariae isolated from common carp specimens during exposure to different physical treatments (temperatures of -18°C, +20°C, +40°C and +60°C) and chemical agents (5% and 10% acetic acid and 10% sodium chloride (NaCl)). Metacercariae lost viability by freezing at -18°C (2 h), heating at 60°C (20 min), incubation in 5% and 10% acetic acid (5 min) and 10% NaCl (2 h). These methods served as models to investigate the effectiveness of food preparation techniques (such as cold and hot smoking, freezing, salting and pickling) on the survival of metacercariae.

Multidisciplinary approach in study of the zoonotic Anisakis larval infection in the blue mackerel (Scomber australasicus) and the largehead hairtail (Trichiurus lepturus) in Northern Taiwan.

BACKGROUND: Anisakid larvae are the food-borne pathogen highly prevalent among numerous marine fishes. Accidental consumption of infected raw or poorly cooked fish fillets may cause anisakiasis. METHODS: This study used the multidisciplinary approach to investigate the occurrence of Anisakis nematodes in commonly consumed fish species, Scomber australasicus and Trichiurus lepturus purchased in Taipei Xinyi traditional fish market. RESULTS: All the Anisakis larvae collected herein were identified morphologically as Anisakis type I or Anisakis type II. The prevalence and the mean intensity of Anisakis larvae collected from S. australasicus was 80.77%, 26.8 (10-32) and 100%, 49.0 (27-70) for T. lepturus. Using molecular analysis, 83.33% (180/216) were identified as Anisakis pegreffii, 6.05% (13/216) as Ascaris typica, 1.85% (4/216) as Ascaris physeteris and 8.80% (19/216) as hybrid genotype (A. pegreffii + Anisakis simplex) in S. australasicus. In T. lepturus, 86.31% (290/336) were identified as A. pegreffii, 2.38% (8/336) as A. typica, and 11.31% (38/336) as hybrid genotype (A. pegreffii + A. simplex [s.s]). The molecular phylogenetic analysis shows two cluster clades, one group includes A. pegreffii complex and the other include Ascaris paggiae, Ascaris brevispiculata, and A. physeteris. CONCLUSION: Thus, A. pegreffii is the most abundant species and may be the potential causes of human infection.

Improving diagnostic performance of the Kato-Katz method for Clonorchis sinensis infection through multiple samples.

BACKGROUND: Clonorchiasis is caused by eating of raw or undercooked freshwater fish containing the larvae of Clonorchis sinensis; the Kato-Katz method is widely applied in diagnosis. The improvement of repeated Kato-Katz smears from multiple stool samples has been well illuminated in many helminths other than C. sinensis. METHODS: A cross-sectional investigation was implemented to capture the epidemiology and risk factors of clonorchiasis among middle school students in Qiyang county, China. Students with complete data of six Kato-Katz thick smears from two stool samples were included in this analysis. Data on the habits of eating raw freshwater fish were also collected and compared. RESULTS: Altogether, 397 students had complete information of six smears, out of which 394 reported the information on eating habits. According to the 'gold' standard by six smears, 77 students (19.4%) were detected with C. sinensis. However, only 45 (11.3%) were detected using a single smear, with an underestimation of 41.6% compared to the 'gold' standard. However, the geometric mean of eggs per gram of feces in detected cases was 126.4 in a single smear, overestimated by 105.2% compared to 61.6 by the 'gold' standard. The linear relationship between prevalence and infection intensity of detected cases based on different smears was significantly negative. The habits of eating raw freshwater fish in the false negative cases was similar to those in the detected cases, but these two groups had significantly higher levels for habits of eating raw freshwater fish than negative individuals. CONCLUSIONS: In low endemicity situations, underestimation of C. sinensis infection could not be avoided based on a limited number of Kato-Katz smears. Thus, repeated smears from at least two stool samples should be considered when an individual eats raw freshwater fish, drug efficacy is evaluated or elimination of C. sinensis is verified. Additionally, when logistics are insufficient for multiple samples to be taken for diagnosis for survey and surveillance in the areas or populations of low endemicity, prevalence accuracy needs to be corrected.

Effectiveness of five flavored Tunisian olive oils on Anisakis larvae type 1: application of cinnamon and rosemary oil in industrial anchovy marinating process.

BACKGROUND: Anisakidosis is caused by the ingestion of raw or undercooked fish or cephalopods containing viable Anisakis larvae. Several natural extracts, oils, essential oils, and their compounds have been tested against Anisakis. In this study the effectiveness of Tunisian olive oil with different spices or plants (cardamom, cinnamon, ginger, laurel, and rosemary) was tested against Anisakis larvae type 1. RESULTS: For the in vitro test, larvae were submerged separately in the oils mentioned above and observed to check viability. Cinnamon oil was the most effective against parasites with lethal time (LT) scores being LT50 = 1.5 days and LT100 = 3 days, followed by rosemary. Laurel, cardamom, and ginger oils were less effective. For the ex vivo experiment, cinnamon, and rosemary oils were tested in anchovy fillets, previously artificially parasitized. Cinnamon was the most effective against parasites (dead after 4 days) as compared to rosemary (7 days). CONCLUSION: The use of cinnamon and rosemary-flavored olive oil in the industrial marinating process can be considered as an efficient alternative to the freezing process required by European Regulation EC No 853/2004 to devitalize Anisakis. © 2019 Society of Chemical Industry.

[Quantitative Analysis of Unicapsula seriolae in Greater Amberjack Associated with Unidentified Food-Borne Disease].

It has been suggested that a myxosporean parasite, Unicapsula seriolae, is responsible for food-borne disease associated with the ingestion of raw greater amberjack. In this study, we quantified U. seriolae in greater amberjack meats involved in food-poisoning episodes. U. seriolae DNA was detected in 26 samples out of 29 samples by means of quantitative real-time PCR(qRT-PCR). The major symptoms were diarrhea and vomiting within 12 hours after consumption. No seasonal trend in the outbreaks was apparent. The number of spores in samples with qRT-PCR-detected U. seriolae DNA ranged from 1.9×105 to 1.7×107 spores/g. However, no spores were detected in greater amberjack purchased from markets. These results indicate that U. seriolae was responsible for the outbreaks. The copy number of DNA in the positive samples was more than 107 copies/g. The ingestion amount was known in 11 of the incidents, and the minimum quantity of spores that caused symptoms was estimated to be 3.8×106 spores/g.

Validation of a commercial kit aimed to the detection of pathogenic anisakid nematodes in fish products.

Anisakids are parasitic nematodes responsible for a zoonosis that occurs following the ingestion of fish and fish products infected with larvae belonging to the genera Anisakis and Pseudoterranova. Rarely Contracaecum is found in association with gastric/intestinal illness, while Hysterothylacium is commonly considered not pathogenic. Although Real Time PCR assays have been recently used with the aim to detect and quantify these parasites in food products, methods applied did not undergo through extensive validation process, a feature highly desirable or mandatory in the case of testing laboratories accredited for the ISO EN 17025:2005. Here, a comprehensive study has been performed to validate a commercial kit based on multiplex real time PCR for the qualitative detection of Anisakis and Pseudoterranova. Inclusivity/exclusivity trials were carried out on DNA from species of the genera Anisakis, Pseudoterranova, Contracaecum, Hysterothylacium and Ascaris, on fish intentionally contaminated with Anisakis spp. and Pseudoterranova spp. and on marine organisms as fish, crustacean and squid to test the commercial kit on a large sample. The assay gave positive amplification for several Anisakis and Pseudoterranova species, while providing no signal for the members of the remaining genera. Each sample was correctly assigned either to Anisakis or Pseudoterranova, thus indicating that no cross-reaction occurred. The LOD was determined using two independent standard curves. Robustness was assayed by using two different thermocyclers in three distinct laboratories with different operators. The establishment of a validation dossier will permit the use of the commercial kit for the detection of Anisakis and Pseudoterranova DNA in fish and fish products intended for human consumption by public or private laboratories, following the requirements regarding the quality assurance processes described in the ISO EN 17025:2005.

Molecular diagnosis of allergy to Anisakis simplex and Gymnorhynchus gigas fish parasites.

BACKGROUND: There has been an increase in the prevalence of hypersensitivity to Anisakis simplex. There are fish parasites other than Anisakis simplex whose allergenicity has not yet been studied. OBJECTIVE: To assess IgE hypersensitivity caused by fish parasite allergens in patients with gastro-allergic symptoms after consumption of fish, shellfish or cephalopods, compared with healthy subjects, pollen allergic individuals and children with digestive symptoms after eating marine food. METHODS: We carried out in vivo tests (skin prick) and in vitro tests (specific IgE determination, Western blot) and component resolved diagnostics (CRD) using microarray analysis in all patients. RESULTS: CRD better detected sensitisation to allergens from marine parasites than skin prick tests and determination of specific IgE by CAP. Sensitisation to Gymnorhynchus gigas was detected in 26% of patients measured by skin prick tests and 36% measured by IgE. CONCLUSIONS: The prevalence of hypersensitivity to marine parasite allergens other than Anisakis simplex should be studied, and the most appropriate technique for this is CRD.

Fish Parasites: A Growing Concern During Pregnancy.

Intestinal parasitic worms affect more than 2 billion people worldwide according to the World Health Organization. Fish-borne parasitic infections are becoming more common with the increasing popularity of sushi, sashimi, Carpaccio, tartare, gefilte, and ceviche. The ingestion of these parasites can cause serve anemia, malabsorption, severe abdominal pain, nausea, vomiting, strong allergic reactions, and gastric ulcers. Knowledge about fish parasites and pregnancy is limited. A literature search on PubMed and Web of Science used the search terms "fish parasites" OR "diphyllobothrium" OR "anisakiasis" OR "pseudoterranova" OR ("food borne parasites" AND "fish") AND "pregnancy" OR "maternal" OR "fetus" OR "fetal" OR "newborn" OR "neonatal" OR "childbirth." No limit was put on the number of years searched. There were 281 publications identified. The abstracts of all of these publications were read. After exclusion of the articles that were not relevant to pregnancy, pregnancy outcome, and fish parasites, there were 24 articles that became the basis of this review. The pathophysiology, altered maternal immunity related to the infection, limited information about fish-borne parasitic infections and pregnancy, and treatments are discussed. The main impact of a fish-borne parasitic infection on pregnant women is anemia and altered immunity, which may increase the risk of a maternal infection. The primary fetal effects include intrauterine growth restriction and preterm delivery.

Validation of the TrichinEasy® digestion system for the detection of Anisakidae larvae in fish products.

Anisakis and other parasites belonging to the Anisakidae family are organisms of interest for human health, because of their high zoonotic potential. Parasites belonging to this family can cause Anisakiasis, a parasitological disease caused by the ingestion of raw, infested fish products. Furthermore, evidence from the EFSA (European Food Safety Authority; EFSA 2010) has highlighted the allergological potential of nematodes belonging to the Anisakis genre. The detection and identification of Anisakidae larvae in fish products requires an initial visual inspection of the fish sample, as well as other techniques such as candling, UV illumination and artificial digestion. The digestion method consists of the simulation of digestive mechanics, which is made possible by the utilization of HCl and pepsin, according to EC Regulation 2075/2005. In this study, a new Anisakidae larvae detection method using a mechanical digestion system called Trichineasy® was developed. A total of 142 fish samples, belonging to 14 different species, were examined to validate the method. A reaction mixture with 100 g of sample, 10 g of pepsin (1:10000 NF) and 50 ml of 10% HCl at 36 ± 1°C for 20 minutes was evaluated to be the best condition for the digestion of fish samples. These parameters have also allowed the detection of viable larvae after digestion. The results confirm this instrumentation as a valuable and safe tool for the detection of Anisakidae larvae in fishery products.

IgE sensitization to the fish parasite Anisakis simplex in a Norwegian population: a pilot study.

The reports on fish parasite Anisakis simplex allergy have increased in countries with high fish consumption in the last decade. In Norway, a high consumption country, the prevalence of immunoglobulin E (IgE) sensitization to A. simplex was still unknown. Thus, our objective was to investigate the sensitization prevalence in this country. At the Haukeland University Hospital, Bergen, Norway, two main groups of surplus serum samples were collected: one from newly recruited blood donors (BDO) and the other from the Allergy laboratory (ALL) after analysing IgE and IgE antibodies. The latter was divided into three series: one containing unsorted sera and two sorted by either Phadiatop(®) ≥0.35 kU(A)/l or total IgE ≥1000 kU/l. The sera were analysed for total IgE and IgE antibodies against A. simplex, shrimp, house dust mite (HDM), cod and cross-reactive carbohydrates (CCDs). The prevalence of IgE sensitization to A. simplex was 2.0%, 2.2% and 6.6% in BDO, the unsorted and Phadiatop(®) positive serum groups, respectively. A considerable degree of cross-sensitization to shrimp and HDM is further suggested. Unspecific binding because of high total IgE or by binding to CCDs seemed to play a minor role. The prevalence of IgE sensitization to A. simplex appears to be lower in a Norwegian population than in other high fish-consuming countries, but might still be overestimated owing to cross-sensitization.

Viability and antigenicity of anisakis simplex after conventional and microwave heating at fixed temperatures.

Inactivation of parasites in food by microwave treatment may vary due to differences in the characteristics of microwave ovens and food properties. Microwave treatment in standard domestic ovens results in hot and cold spots, and the microwaves do not penetrate all areas of the samples depending on the thickness, which makes it difficult to compare microwave with conventional heat treatments. The viability of Anisakis simplex (isolated larvae and infected fish muscle) heated in a microwave oven with precise temperature control was compared with that of larvae heated in a water bath to investigate any additional effect of the microwaves. At a given temperature, less time was required to kill the larvae by microwaves than by heated water. Microwave treatment killed A. simplex larvae faster than did conventional cooking when the microwaves fully penetrated the samples and resulted in fewer changes in the fish muscle. However, the heat-stable allergen Ani s 4 was detected by immunohistochemistry in the fish muscle after both heat treatments, even at 70°C, suggesting that Ani s 4 allergens were released from the larvae into the surrounding tissue and that the tissues retained their allergenicity even after the larvae were killed by both heat treatments. Thus, microwave cooking will not render fish safe for individuals already sensitized to A. simplex heat-resistant allergens.

Fatal bilateral dioctophymatosis.

Dioctophyma renale is a parasite that frequently occurs in animals but rarely in humans. The present report describes the clinical observations of a D. renale infection in a 51-yr-old woman. Its clinical signs and diagnostic findings were unspecific until giant worms were observed in the urine and histological findings confirmed it was a D. renale infection. She refused treatment and died of bilateral renal function failure. This is the first confirmed report to follow the natural progression of D. renale infection in a human. Here, we discuss a conservative therapeutic approach and features associated with this parasitic infection.

Actividad IN VIVO del aceite esencial de Origanum elongatum frente a larvas L3 de Anisakis pegreffii / IN VIVO activity of essential oil Origanum elongatum against larva L3 of Anisakis pegreffii

En este trabajo se aborda la posible actividad larvicida in vivo del aceite esencial de Origanumelongatum, recolectado en Marruecos, frente a las larvas L3 de Anisakis pegreffii, que parasitan distintas especies marinas. Los resultados obtenidos son demostrativos del interés potencial de esteaceite esencial como preventivo de la infección por Anisakis, tras ingestión del pescado parasitado(AU)

Anisakiasis is an emerging zoonotic disease caused by species of the genus Anisakis. In humans, this parasite is manifested by digestive symptoms. In the virtual absence of effective treatments against this infection, our working group has initiated a series of investigations aimed at finding natural products such as essential oils and their major components, which might be of interest in the treatment of the infectious form of these zoonoses. OBJECTIVE: Establishment of the possible in vivo activity of essential oil of O. elongatum, against L3 larva of Anisakis pegreffii. METHODOLOGY: For the study in vivo, parasites were isolated from the host Scomber japonicas (mackerel) and Trachurus trachurus (horse mackerel). The experimental animals (female Wistar rats) were infected with 6 Anisakis larva by gastric catheter, this technique was used also for the administration of O. elongatum (46.9 mg / 0.5 ml of olive oil), according to the following guidelines: infection and joint treatment and sacrifice at 4 hours. Parallel to this, a control test was performed, administering 0.5 ml olive oil together with six larvae of the parasite to a group of animals. The identification of the larvae was carried out using molecular techniques (PCR-RFLP). The identification of the main components of essential oil was performed by GC-MS(AU)

Quantification of Anisakis simplex allergens in fresh, long-term frozen, and cooked fish muscle.

Fish-borne parasitic zoonoses such as Anisakiasis were once limited to people living in countries where raw or undercooked fish is traditionally consumed. Nowadays, several factors, such as the growing international markets, the improved transportation systems, the population movements, and the expansion of ethnic ways of cooking in developed countries, have increased the population exposed to these parasites. Improved diagnosis technology and a better knowledge of the symptoms by clinicians have increased the Anisakiasis cases worldwide. Dietary recommendations to Anisakis-sensitized patients include the consumption of frozen or well-cooked fish, but these probably do not defend sensitized patients from allergen exposure. The aim of our work was to develop a sensitive and specific method to detect and quantify Anisakis simplex allergens in fish muscle and its derivatives. Protein extraction was made in saline buffer followed by preparation under acid conditions. A. simplex antigens were detected by IgG immunoblot and quantified by dot blot. The allergenic properties of the extracts were assessed by IgE immunoblotting and basophil activation test. We were able to detect less than 1 ppm of A. simplex antigens, among them the allergen Ani s 4, in fish muscle with no cross-reactions and with a recovery rate of 82.5%. A. simplex antigens were detected in hakes and anchovies but not in sardines, red mullets, or shellfish. We detected A. simplex allergens in cooked hakes and also in hake stock. We proved that A. simplex allergens are preserved in long-term frozen storage (-20 degrees C +/- 2 degrees C for 11 months) of parasitized hakes. Basophil activation tests have proven the capability of the A. simplex-positive fish extracts to induce allergic symptoms.

Different Th1/Th2 responses to Anisakis simplex are related to distinct clinical manifestations in sensitized patients.

Anisakis simplex is a fish parasite capable of inducing inflammatory and allergic reactions in humans who eat raw or undercooked fish. The aim of this study was to characterize the T helper type 1 (Th1)/Th2 immune response to parasite crude (CE) and thermostable (TsE) extracts in A. simplex-sensitized patients. Cytokines were quantified by a multiplex flow cytometric method in short-term whole blood cultures. Higher concentrations of IL-2, IL-4 and IL-5, measured with the CE and TsE, were found in patients than in controls. Patients showing urticaria-angio-oedema or anaphylaxis (UA/A) had higher total and specific IgE levels than those with gastrointestinal symptoms (GI). The UA/A group showed high levels of IL-5 and IL-4 and low expression of IFN-gamma than the GI group. The GI group had significantly higher IFN-gamma/IL4 ratio than the UA/A group. Four patients with severe GI symptoms reporting a delayed skin test reaction had very low values of specific IgE to A. simplex and higher IFN-gamma/IL4 ratios than that observed in other patients belonging to the GI group. This short-term whole blood test can be useful for immune response characterization in Anisakis infection and showed that heated parasite antigens are still capable of inducing cellular immune response in sensitized patients.