Eosinophilic gastroenteritis and Anisakis

Worm globalization

We report the first case of eosinophilic pleural effusion due to Anisakis spp. infection in a 39-years-old European subject hospitalized for worsening dyspnoea and abdominal and thoracic pain. Lung CT scan showed bilateral pleural effusion; thoracentesis revealed significant eosinophilia (45%), with normal eosinophils in the blood. Microbiological tests on pleural effusion were negative for bacteria, SARS-CoV-2, tuberculosis, fungi and parasites. The patient used to eat raw fish; Western blot was positive for Anisakis spp. in blood and pleural effusion. In the era of globalization, unusual parasitic infections should be considered also in nonendemic countries, especially in patients with unexplained eosinophilia.

Analysis of the prevalence and species of Anisakis nematode in Sekisaba, Scomber japonicus caught in coastal waters off Saganoseki, Oita in Japan

Anisakidosis is developed by ingesting Anisakis in marine fish including the chub mackerel, Scomber japonicus without proper pre-treatment such as cooking or freezing. Two sibling species of Anisakis are found in S. japonicus from Japanese waters and the prevalence and species of Anisakis in the fish depend on sea area. For example, Anisakis simplex sensu stricto is found in the Pacific stock of S. japonicus, while Anisakis pegreffii is found in the Tsushima Warm Current stock. S. japonicus caught in the Bungo Channel, off the coast of Saganoseki in Oita Prefecture, which is branded as Sekisaba, inhabits a very limited area; however, the infection states of Anisakis found in Sekisaba remain unclear. In this study, we compared the infection states of Anisakis in Sekisaba with those in S. japonicus caught in South Oita area and Nagasaki Prefecture. All of Anisakis from Nagasaki Prefecture were A. pegreffii, while most of them found in Sekisaba and fish from South Oita area were A. simplex s.s.. Interestingly, the prevalence of Anisakis in Sekisaba was significantly lower than those of two other areas. This may be reflected that Sekisaba might belong to a distinct stock of S. japonicus varying from other stocks.

Anisakis sensitization in different population groups and public health impact: A systematic review

Anisakis simplex spp. sensitization rates have increased worldwide, with a significant impact on health-care systems. To date, no clear-cut diagnostic criteria and laboratory algorithm have been established, so anisakiasis still represents an under-reported health problem whose clinical manifestations, when present, mimic the much more common allergic and digestive disorders. Aim of the study was to systematically review the available literature on the prevalence of sensitization against Anisakis in the general population and in specific population groups, taking into account the impact of the different available diagnostic techniques on the epidemiological data. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, relevant papers reporting Anisakis sensitization epidemiological data were found covering a period ranging from 1996 to February 2017. Overall, 41 studies comprising 31,701 participants from eleven countries were included in the qualitative synthesis. General asymptomatic population resulted sensitized to Anisakis in 0.4 to 27.4% of cases detected by means of indirect ELISA or ImmunoCAP specific IgE detection, and between 6.6% and 19.6% of the samples by Skin prick test (SPT). Occupationally exposed workers (fishermen, fishmongers and workers of fish-processing industries) documented specific IgE between 11.7% and 50% of cases, whereas SPT positivity ranged between 8% and 46.4%. Symptomatic allergic patients to any kind of allergen were found to be positive to Anisakis specific IgE detection between 0.0% (in children with mastocytosis) to 81.3% (among adults with shellfish allergy). Results highlighted that hypersensitivity prevalence estimates varied widely according to geographical area, characteristics of the population studied, diagnostic criteria and laboratory assays. Further studies are needed to overcome the documented misdiagnosis by improving the diagnostic approach and, consequently, providing more affordable estimates in order to address public health interventions on populations at high risk of exposure to Anisakis and to tailor health services related to specific groups.

Increased number of eosinophils in ascites is associated with intestinal anisakidosis

The aim of this study was to evaluate the association between eosinophils in ascites and the diagnosis of intestinal anisakidosis in patients with peritoneal signs on physical examination. We reviewed retrospectively 16 patients diagnosed with intestinal anisakidosis, evaluated between 2012 and 2015. All patients had ingested raw anchovies. The analysis of ascites fluid in ten of these patients was compared with that of 15 patients with ascites and other abdominal pathology (except liver cirrhosis). All patients had an increased number of white blood cells in the ascites fluid. The eosinophil count was significantly higher in patients with intestinal anisakidosis (P < 0.01). All patients had a good outcome. Increased eosinophils in ascites fluid is strongly associated with the diagnosis of intestinal anisakidosis.

Anisakis - immunology of a foodborne parasitosis

Anisakis species are marine nematodes which can cause zoonotic infection in humans if consumed in raw, pickled or undercooked fish and seafood. Infection with Anisakis is associated with abdominal pain, nausea and diarrhoea and can lead to massive infiltration of eosinophils and formation of granulomas in the gastrointestinal tract if the larvae are not removed. Re-infection leads to systemic allergic reactions such as urticarial or anaphylaxis in some individuals, making Anisakis an important source of hidden allergens in seafood. This review summarizes the immunopathology associated with Anisakis infection. Anisakiasis and gastroallergic reactions can be prevented by consuming only fish that has been frozen to -20°C to the core for at least 24 hours before preparation. Sensitization to Anisakis proteins can also occur, primarily due to occupational exposure to infested fish, and can lead to dermatitis, rhinoconjunctivitis or asthma. In this case, exposure to fish should be avoided.

You Are What You Eat: A Case of Nematode-Induced Eosinophilic Esophagitis

Human anisakiasis is acquired through eating raw or undercooked saltwater fish or squid. Infestation with living larvae caused by eating parasitized fish often times results in gastroenteritis. It mainly involves the stomach and small intestine with no reported cases of eosinophilic esophagitis caused by Anisakidea. A 41-year-old man presented for the evaluation of 1 year of dysphagia to solid foods and was found to have endoscopic findings consistent with eosinophilic esophagitis with pathology showing 100 eosinophils per high-power field. During endoscopy, a roundworm, later identified as Anisakidae species, was found. Patient was treated with a 6-week course of albendazole with symptomatic, endoscopic, and histologic improvement.

Riesgos para la salud asociados al parasitismo del pescado por nematodos de los géneros Anisakis y Pseudoterranova/Health hazards related to occurrence of parasites of the genera Anisakis and Pseudoterranova in fish

Anisakiasis, also named larva migrans visceral or eosinophilic granuloma, is a widespread ictiozoonosis. Occurrence of this parasitic disease in Spain has risen dramatically in the last decade. The presence of Anisakis spp. and related species in fish presents both a potential public health threat to humans and also an important cause of economic losses for fish processing industries. Anisakiasis is transmitted through comsumption of fish and squid that harbor the third stage larvae of parasites belonging to the Anisakidae family, both raw or minimally processed. Changes in the way that fish is handled and processed after its capture and also in how fish is cooked at home and elsewhere, could explain why this parasitic disease is progressing so rapidly during the second half of this century. The importance of this parasitosis is growing as a consequence both of the high incidence of Anisakis spp. in fish and the widespread consumer ignorance of this potential threat.

Anisakiasis Causing Acute Dysentery in Malaysia

Human anisakiasis is a zoonosis acquired by eating raw or undercooked infected seafood. Herein, we report a case of acute dysentery caused by anisakiasis in a 64-year-old man in Malaysia. A colonoscopy was performed and a nematode larva was found penetrating the mucosa of the ascending colon. Bleeding was observed at the site of penetration. Y-shaped lateral epidermal cords were seen from the cross section of the worm, which is a prominent feature of Anisakis larva. Molecular analysis using polymerase chain reaction of cytochrome oxidase 2 (cox2) gene confirmed the specimen to be larva of Anisakis simplex.

Helminthosis and eosinophilia in Spain (1990-2015)

The finding of blood eosinophilia in a patient is a relatively frequent reason to refer him/her to a Clinical Department of Infectious Diseases. The doctor usually intends to rule out a parasitic disease in the autochthonous population, travelers or immigrants. It is uncommon for an eosinophilia to be produced by protozoa infection, whereas helminth parasites are more frequently associated with an increase of eosinophil counts in the infected patient. Eosinophilia can be the only abnormal finding, or it could be part of more complex clinical manifestations suffered by the patient. Furthermore, many, but not all, helminth infections are associated with eosinophilia, and the eosinophil level (low, high) differs according to parasite stages, helminth species, and worm co-infections. The purpose of the present article is to carry out a systematic review of cases and case series on helminth infections and eosinophilia reported in Spain from 1990 to 2015, making a distinction between autochthonous and imported (immigrants and travelers) cases, and studying their relationship with immunodepression situations.

Allergic reactions to Anisakis found in fish

The food-borne parasite Anisakis is an important hidden food allergen. Anisakis is a parasitic nematode which has a third-stage larval form that infects mainly fish, and ingestion of contaminated seafood can result in severe allergic reactions. Symptoms experienced due to exposure to this parasite include gastrointestinal disorders, urticaria, dermatitis, asthma and even anaphylaxis. Accurate prevalence data of allergic sensitisation to Anisakis are difficult to estimate due to the lack of well-designed population-based studies. Current diagnostic approaches rely on the detection of serum IgE antibodies to allergenic proteins, which however demonstrate considerable immunological cross-reactivity to other invertebrate allergens. While exposure to this parasite seems to increase due to the increasing consumption of seafood worldwide, the immunology of infection and allergic sensitization is not fully understood.

Parametrial anisakidosis

Anisakidosis is a parasitic infection caused by anisakid nematodes in the genera Anisakis and Pseudoterranova. Infection is not uncommon in the United States due to increased raw seafood consumption. We report the first known case of parametrial anisakidosis in a 42-year-old woman and review existing literature.

Spontaneous splenic rupture and Anisakis appendicitis presenting as abdominal pain: a case report

Introduction

Anisakidosis, human infection with nematodes of the family Anisakidae, is caused most commonly by Anisakis simplex. Acquired by the consumption of raw or undercooked marine fish or squid, anisakidosis occurs where such dietary customs are practiced, including Japan, the coastal regions of Europe and the United States. Rupture of the spleen is a relatively common complication of trauma and many systemic disorders affecting the reticuloendothelial system, including infections and neoplasias. A rare subtype of rupture occurring spontaneously and arising from a normal spleen has been recognized as a distinct clinicopathologic entity. Herein we discuss the case of a woman who presented to our institution with appendicitis secondary to Anisakis and spontaneous spleen rupture.

Case presentation

We report the case of a 53-year-old Caucasian woman who presented with hemorrhagic shock and abdominal pain and was subsequently found to have spontaneous spleen rupture and appendicitis secondary to Anisakis simplex. She underwent open surgical resection of the splenic rupture and the appendicitis without any significant postoperative complications. Histopathologic examination revealed appendicitis secondary to Anisakis simplex and splenic rupture of undetermined etiology.

Conclusions

To the best of our knowledge, this report is the first of a woman with the diagnosis of spontaneous spleen rupture and appendicitis secondary to Anisakis simplex. Digestive anisakiasis may present as an acute abdomen. Emergency physicians should know and consider this diagnosis in patients with ileitis or colitis, especially if an antecedent of raw or undercooked fish ingestion is present. Spontaneous rupture of the spleen is an extremely rare event. Increased awareness of this condition will enhance early diagnosis and effective treatment. Further research is required to identify the possible risk factors associated with spontaneous rupture of the spleen.

Anisakiasis, an underestimated infection: effect on intestinal permeability of Anisakis simplex-sensitized patients

Anisakis simplex is a parasite that, if present in uncooked and contaminated saltwater fish, can invade the human gut. Two different clinical situations are recognized: the first, known as a gastrointestinal disease, varying from an asymptomatic episode to vomiting and diarrhea, and the second, classified as an adverse reaction to food, characterized by a wide spectrum of allergic reactions like rhinitis, conjunctivitis, or even anaphylaxis causing hypotension and/or shock. The intestinal epithelium, the major defense system against external molecules, represents an open gate for toxins and allergens if its protective function is compromised. Previous data have demonstrated a strict relationship between an altered intestinal permeability (I.P.) and worsening of the clinical manifestations in patients with adverse reactions to the food. In this article we evaluated the sensitization to A. simplex among patients who referred clinical symptoms of allergy. All subjects underwent commonly used alimentary skin prick test for food allergens, to which Ani s1, an A. simplex allergen, was added. In addition, in A. simplex-sensitized subjects, I.P. was determined upon their enrolment to the study (time 0) and after 6 months of consuming a raw fish-free diet (time 6). Five hundred and forty subjects were screened, and 170 had a positive skin prick test, 87 (51.2%) of whom were positive to Ani s1. Increased I.P. was evidenced in A. simplex-sensitized subjects with worse clinical symptoms, which receded after 6 months' elimination of raw seafood. With our data we demonstrated that the alimentary habit to eat raw fish represents a high risk for the integrity of the intestinal mucosa, and we suggest that this pathological situation may constitute an ideal, under-estimated, open gate for molecules that predispose to other, more important pathologies.

Anisakis pegreffii-induced airway hyperresponsiveness is mediated by gamma interferon in the absence of interleukin-4 receptor alpha responsiveness

Infection with the fish parasite Anisakis following exposure to contaminated fish can lead to allergic reactions in humans. The present study examined the immunological mechanisms underlying the development of allergic airway inflammation in mice after different routes of sensitization to Anisakis. Wild-type and interleukin-4 receptor alpha (IL-4Ralpha)-deficient BALB/c mice were sensitized intraperitoneally with live or heat-killed Anisakis larvae or by intranasal administration of an Anisakis extract and were subsequently challenged intranasally with an Anisakis extract. Both routes of sensitization induced IL-4Ralpha-dependent allergic airway responses, whereas allergen-specific antibody responses developed only when mice were sensitized intraperitoneally. Intranasal sensitization induced airway hyperresponsiveness (AHR) in wild-type mice only, showing that AHR was IL-4/IL-13 dependent. Unexpectedly, infection with Anisakis larvae induced AHR in both wild-type and IL-4Ralpha-deficient mice. IL-4Ralpha-independent AHR was mediated by gamma interferon (IFN-gamma), as evidenced by the fact that in vivo neutralization of IFN-gamma abrogated AHR. Together, these results demonstrate that both infection with larvae and inhalational exposure to Anisakis proteins are potent routes of allergic sensitization to Anisakis, explaining food- and work-related allergies in humans. Importantly for diagnosis, allergic airway inflammation can be independent of detectable Anisakis-specific antibodies. Moreover, depending on the route of sensitization, AHR can be induced either by IL-4/IL-13 or by IFN-gamma.

Human antibody recognition of Anisakidae and Trichinella spp. in Greenland

High levels of total IgE are observed among children in Greenland. To evaluate the extent to which Anisakidae and Trichinella spp. contribute to the high total IgE level, an ELISA and a western blot were developed for the detection of IgG antibodies to Anisakidae, based on excretory/secretory antigens from Anisakidae larvae. Western blots with Anisakidae and Trichinella antigens discriminated between Anisakidae and Trichinella infections, enabling cross-reactivity between the two parasite infections to be eliminated. Serum samples from 1012 children in Greenland were analysed for specific antibodies to Anisakidae and Trichinella. Eleven children were IgG-positive for Trichinella and nine were IgG-positive for Anisakidae, indicating a relatively low prevalence of both infections among children in Greenland. Faecal samples from 320 children were also examined for other intestinal parasites. Enterobius vermicularis was found in one sample and Blastocystis hominis in 32 samples, but no other intestinal parasites were identified. In total, 304 children had elevated total IgE levels. There was a significant association between Trichinella seropositivity and high levels of total IgE, but not between Anisakidae seropositivity and total IgE. The data indicate that parasitic infections alone do not explain the high level of total IgE observed among children in Greenland.

Evaluation by the skin prick test of Anisakis simplex antigen purified by affinity chromatography in patients clinically diagnosed with Anisakis sensitization

Anisakis simplex crude extracts (CE) (IPI, ASAC and ALK-ABELLÓ), A. simplex larval antigens purified using a column of IgG anti-A. simplex (PAK) or a column of IgG anti-Ascaris suum (PAS), antigen eluted from columns of IgG anti-A. suum (EAS) and an A. suum adult CE were assayed by the skin prick test. Thirty percent of assayed patients showed a negative reaction in the Anisakis skin prick test. Of 70% positives, two patients had a weal greater than that produced by histamine with the A. simplex extract from ABELLÓ and IPI. The A. suum skin prick test was positive in 35% of patients, with a lower reaction than that observed with the A. simplex extract from IPI in 57% of the sera and a higher reaction in 28% of the sera. All patients with positive reactions with the crude extract also showed positive weals with the two purified antigens, PAK and PAS. All patients, except three, with a reaction to A. suum antigen, were positive to the EAS antigen. In five patients the weal size produced by PAS was greater than that observed with PAK, whereas in another six patients the contrary was observed. Only one of these six patients did not react to EAS antigen, coincident with the patient showing only a slight increase (7%) in the weal size induced by PAK vs. PAS. When the EAS antigen was tested on patients positive to both PAK and PAS, six patients presented a weal size of >30% and only three patients who were positive to PAS did not react to the EAS antigen. These three patients were also negative against the A. suum CE. Purification by affinity chromatography eliminates from the PAS antigen the proteins responsible for producing cross-reactions with Ascaris (present in the EAS antigen).

Pathology of non-infective gastritis

The discovery of Helicobacter pylori and its intimate role in the development of the most common form of chronic gastritis has elicited a much-needed interest in non-neoplastic gastric pathology. This has been paralleled by an increase in upper endoscopic examinations, which allow recognition of novel patterns and distribution of mucosal injury. Numerous attempts at classification have been made, most based on the acuteness or chronicity of gastric mucosal injury. In this review, we will not offer a new classification but present a detailed description of the major clinicopathological entities, based either on the salient morphological features or the underlying aetiologies, i.e. iatrogenic, autoimmune, vascular or idiopathic.

Chronic Anisakiasis of the Ascending Colon Associated with Carcinoma

Chronic anisakiasis of the colon is rare and difficult to diagnose. We report a case of chronic anisakiasis associated with advanced colonic carcinoma. A 69-year-old man was admitted for abdominal pain, diarrhea, and urticaria. Right hemicolectomy was performed because of an obstruction of the ascending colon and a palpable tumor of the right lower abdomen. The lesion was thought to be located in the deeper layers of the ascending colon. Preoperative examinations failed to detect the coexistence of anisakiasis and carcinoma of the colon. The anisakis was identified morphologically in the intestinal wall of the resected specimen and by an elevated titer of an IgE antibody specific to the parasite. Seventy-five cases of colonic and rectal anisakiasis, including the present case, have been reported in Japan. This is the only reported case of anisakiasis to appear in association with colonic carcinoma.

[Anisakiasis: an infestation to be known by surgeons]

BACKGROUND

Anisakis infestation is related to the consumption of raw or undercooked fish. It can cause allergic reactions, or abdominal pain when the gastrointestinal tube is involved. Its incidence is rising in Europe.

OBJECTIVE

To analyze a group of patients complaining of right iliac fossa pain with ileitis or colitis and establish its relationship with Anisakis spp. infection.

PATIENTS AND METHODS

During a 3-months period, 28 patients with abdominal pain were referred to the hospital with a diagnosis of ileitis or colitis by imaging, endoscopy or surgery. Specific serology for Anisakis was performed in all of them.

RESULTS

At imaging study, 14 patients had ileitis or colitis, three intestinal obstruction and one acute appendicitis. Fourteen patients were operated on and 7 of them underwent resection; histopathologic diagnosis were eosinophilic ileitis (2 cases) or colitis (3 cases), non specific ileitis (1 case) and Crohn's disease (1 case). Another patient had an endoscopic biopsy that concluded eosinophilic colitis. Anisakis serology was positive in 25 (89%), negative in two and unknown in one. All patients were discharged uneventfully.

CONCLUSIONS

Digestive anisakiasis may present as acute abdomen. Surgeons should know and consider this diagnosis in patients with ileitis or colitis, moreover if an antecedent of raw or undercooked fish ingestion is present. A conservative approach is best performed but the clinical picture can require an emergent laparotomy.

The physiological and pathophysiological roles of eosinophils in the gastrointestinal tract

Eosinophils and the gastrointestinal tract interact in an intimate and enigmatic relationship. Under healthy conditions, the presence of eosinophils is limited almost exclusively to the digestive tract mucosa where they exert several effector and immunoregulatory functions. While their precise function in the gastrointestinal tract is not completely understood, it is likely that, together with different T cell subsets, eosinophils are involved in maintaining the immunologic homeostastis across the mucosal barrier under resting conditions. Eosinophils also play a role in several inflammatory conditions, such as intestinal infections, hypersensitivity reactions, primary eosinophilic inflammations and several other chronic intestinal disorders. Depending on the responsible trigger, their effects may be beneficial or detrimental. Here, we discuss the available information regarding the physiological and pathological functions of eosinophils within the gastrointestinal tract.

[Gastrointestinal anisakiasis. Study of a series of 25 patients]

INTRODUCTION

Infection with the parasite Anisakis simplex is common in Japan and northern European countries. The number of reported cases in Spain has increased since the first description in 1991. The aim of the present study was to evaluate the incidence, clinical patterns, histopathological lesions, treatment, and outcome of Anisakis simplex infection in our environment.

MATERIAL AND METHOD

Cases of gastrointestinal anisakiasis diagnosed in our center from December 1999 to January 2002 were studied. Only patients with detection of the parasite in oral endoscopy or the surgical specimen and those with elevated levels of specific IgE to Anisakis simplex, a clinical picture compatible with anisakiasis, or a history of raw fish intake were included. Epidemiological, clinical and laboratory data, as well as diagnostic, histopathologic and therapeutic features, and outcome in these patients were recorded.

RESULTS

Twenty-five cases of gastrointestinal anisakiasis were diagnosed during the study period, representing an incidence of 3.87 cases per 100 000 inhabitants/year. All the patients had ingested raw anchovies. Two groups were observed. The first group was composed of 10 patients with a gastric form of the infection, in which the main symptom was epigastralgia (90%). Oral endoscopy was performed in all patients and the parasite was detected in five (50%). The second group was composed of 15 patients with intestinal involvement in which the main manifestations were symptoms mimicking appendicitis (80%). The most frequent finding of laparotomy and/or imaging tests (abdominal ultrasonography, intestinal transit, abdominal CAT) was terminal ileitis (80%). Seven patients underwent surgery: intestinal resection was performed in four with detection of Anisakis simplex in three. Eosinophilic infiltration was found in all surgical specimens. Treatment was symptomatic in most of the patients and outcome was favorable in all.

CONCLUSIONS

Infection with Anisakis simplex should be investigated in patients with abdominal pain after intake of raw fish, ileitis of unclear origin, or eosinophilic gastroenteritis.

Measurement of serum levels of eosinophil cationic protein in the diagnosis of acute gastrointestinal anisakiasis

Thirty-two patients with abdominal pain and/or intestinal pseudo-obstruction who had consumed raw or undercooked fish in the previous 72 h, were included in a study of anisakiasis, a parasitation of the human gastrointestinal tract by third stage Anisakis simplex larvae. Skin prick test (SPT) against A. simplex were positive in all the patients. High median eosinophil cationic protein (ECP) serum concentrations (> 15 mg/L) at day 0 with normal serum levels at day 30 and a rise of median total and specific IgE against A. simplex at day 30, were observed. We conclude that a raised serum level of ECP in the first 72 h from the onset of symptoms coinciding with a positive SPT against A. simplex and high total and specific immunoglobulin (IgE) in the first month after the parasitation, could be a useful tool in the diagnosis of gastrointestinal anisakiasis, even if the parasite cannot be isolated.

Fragility of the esophageal mucosa: a pathognomonic endoscopic sign of primary eosinophilic esophagitis?

BACKGROUND

Primary eosinophilic esophagitis, a chronic inflammatory disorder of the esophagus, evokes recurrent dysphagia. Endoscopy is often unremarkable, and no consensus exists regarding management of resultant dysphagia. The response of a series of patients with primary eosinophilic esophagitis to dilation is reported together with a description of a possibly pathognomonic sign: fragile esophageal mucosa, for which the term "crêpe-paper" mucosa is introduced.

METHODS

Five men underwent endoscopy because of dysphagia confirmed (clinically, endoscopically, and histologically) to be caused by primary eosinophilic esophagitis and were treated by bouginage.

OBSERVATIONS

All patients had extremely fragile, inelastic, and delicate mucosa, which tore easily even with minor trauma. After the procedure, patients remained asymptomatic for 3 to 24 months.

CONCLUSIONS

Primary eosinophilic esophagitis is characterized by fragile esophageal mucosa that readily tears in response to minor trauma during otherwise uneventful diagnostic endoscopy. This "crêpe-paper" sign may alert endoscopists to the presence of the disease when other mucosal alterations are lacking. Dilation is effective for patients with symptoms with minimal morbidity, despite development of disquieting lesions in response to the procedure.

Anisakis simplex: dangerous--dead and alive?

The risk of infection with Anisakis simplex and related parasites of fish has been recognized for some time, but it is now emerging that ingestion of material from dead parasites in food is also potentially dangerous. The resulting allergic reactions range from rapid onset and potentially lethal anaphylactic reactions to chronic, debilitating conditions. This review discusses the problems and clinical implications associated with A. simplex, other related conditions, and the way in which disease manifestations vary from person to person.

Idiopathic eosinophilic esophagitis is associated with a T(H)2-type allergic inflammatory response

BACKGROUND

Idiopathic eosinophilic esophagitis (IEE) is a chronic-inflammatory disorder of the esophagus of unknown origin. The established cornerstone of diagnosis is a dense infiltration of the esophagus with eosinophils, but neither the precise pattern of inflammatory cell infiltration nor the mechanisms that likely contribute to induction and maintenance of the inflammatory response have been described.

OBJECTIVE

The intention of this study was to characterize the esophageal inflammatory infiltrate and the expression of cytokines in the esophagus in this disease. In addition, we searched for immunologic abnormalities of blood leukocytes to exclude major primary hyporeactive and hyperreactive conditions of the immune system.

METHODS

Infiltration of inflammatory cells in the esophagus, stomach, and duodenum was analyzed by immunohistochemistry through use of mAbs against lineage-associated molecules. Cytokine expression was measured by ELISA and immunohistochemical analysis. Lymphocyte subpopulations in blood were determined by means of flow cytometry.

RESULTS

High eosinophil infiltration into the esophageal squamous epithelium was observed in patients with IEE but not in control subjects. Interestingly, increased T-cell and mast cell numbers were also found within the epithelium in these patients. In contrast, the numbers of inflammatory cells were not increased in the stomach and duodenum in patients with IEE, suggesting a specific inflammatory process within the esophagus. Moreover, increased expression of IL-5 and TNF-alpha was observed in esophageal epithelial biopsy specimens. The distribution of lymphocyte subsets in the peripheral blood and their capacity to generate cytokines did not reflect the changes observed at the inflammatory site.

CONCLUSIONS

IEE is a selective inflammatory response of the esophagus. T cells, IL-5, eosinophils, and IgE-mediated mechanisms appear to be involved, giving rise to the possibility that allergic reactions might play a role in the pathogenesis of the disease.

Emerging helminth zoonoses

As our ability to recognise and diagnose human disease caused by helminth parasites has improved, so our understanding of the epidemiology and clinical manifestations of these diseases has improved. Humans can develop patent infection with a wide range of helminth parasites, whose natural host is another vertebrate. Rather than focusing on a comprehensive review of zoonotic helminth infections, this review describes in detail examples of zoonotic helminth infections that have newly appeared in human populations, or have existed but are increasing in incidence or geographic range. Examples include intestinal capillariasis, anisakidosis, eosinophilic enteritis, oesophagostomiasis and gnathostomiasis. Potential reasons for the emergence of these infections, including changes in social, dietary or cultural mores, environmental changes, and the improved recognition of heretofore neglected infections often coupled with an improved ability to diagnose infection are discussed.

Isolation and characterization of a major allergen from the fish parasite Anisakis simplex

BACKGROUND

Ingestion of raw or undercooked fish can lead to infection of human subjects by the fish parasite Anisakis simplex, a disease known as anisakiasis or anisakidosis. Patients sensitized to this fish parasite show high levels of total and specific IgE. Cross-reactions seem to explain the fact that specific IgE antibodies are also found in a high number of normal subjects, as reported in other parasitoses.

OBJECTIVE

We sought to purify and characterize a major IgE-binding protein from the parasite.

METHODS

A protein was purified from the crude parasite extract by means of ethanol precipitation and reversed-phase HPLC. Its clinical relevance was tested on 20 parasite-positive sera by using IgE and IgG4 immunoblotting. A monospecific human serum was used to study its localization in the parasite body.

RESULTS

A 24-kd protein was purified, to which only 45% of the sera had specific IgG4, but 85% of sera had specific IgE. The protein was present only in the excretory gland, as shown by immunohistochemistry. N-terminal amino acid sequence (17 residues) showed no homology to previously described proteins.

CONCLUSION

A simplex contains a potent allergen in the excretory gland. This major parasite allergen, named Ani s 1, could have important clinical relevance, as shown by the high number of positive sera in the specific IgE immunoblotting.

Incidence of sensitivity to Anisakis simplex in a risk population of fishermen/fishmongers

BACKGROUND

Anisakis simplex, a fish and cephalopodes parasite, can cause either gastrointestinal symptoms or allergic reactions in humans on eating/handling contaminated fish.

OBJECTIVE

The aim of our study was to determine the capacity of Anisakis simplex to induce specific IgE production and allergic reactions following eating and handling fish in a population at risk.

METHODS

We determined the levels of total IgE, specific IgE, and eosinophil count in 28 fishermen/fishmongers (group A) and 15 healthy donors (group B). A skin prick test (SPT) with extracts from Anisakis and the most common species of fish in our country, were also carried out.

RESULTS

Specific IgE to Anisakis were found in 14 subjects of group A (13 of them had a positive SPT to the same extract) and none of group B (only one subject had a positive SPT). The SPT with fish extracts was positive in 4 patients of group A but in none of group B. Subjects in group A with specific IgE to Anisakis showed higher total IgE levels and eosinophil counts compared with either other individuals of the same group or to those of group B.

CONCLUSIONS

These results indicate that fishermen/fishmongers are a population at risk for Anisakis simplex sensitization and suggest that this kind of sensitization should also be investigated not only in subjects like fishermen/fishmongers who live in countries where fish is likely to be contaminated with Anisakis simplex parasites, but also in those who handle fish for other reasons.

Immunopathogenesis of human gastrointestinal infection by Anisakis simplex

BACKGROUND

Anisakis simplex is a parasite of fish, and in the case of human infestation, it should be considered as a possible cause of gastrointestinal disease, especially in countries where raw or undercooked fish is a frequent food. Clinical features of anisakiasis may simulate acute abdominal pain, such as that found in patients with gastric ulcers, appendicitis, and Crohn's disease. Furthermore, many cases of anisakiasis are diagnosed as eosinophilic gastroenteritis, which is a broad term for a specific disease.

OBJECTIVE

The purpose of this study was to investigate the immunopathogenesis of human gastrointestinal infestation by A simplex.

METHODS

Thirteen intestinal biopsy specimens from patients with anisakiasis were analyzed for the presence of messenger (m)RNA for different cytokines and inflammatory mediators by RT-PCR. Specific IgE, eosinophil cationic protein, eosinophil protein X, and tryptase levels were measured in each patient's serum. Also, cell cultures were set up with lymphocytes from some patients and stimulated in vitro with Anisakis and Ascaris antigens.

RESULTS

We performed immunologic phenotyping in 13 patients. All patients underwent biopsy after emergency surgery caused by episodes of acute abdominal pain. In all cases inflammatory infiltrate composed of eosinophils and lymphocytes was found in the intestinal wall. We demonstrated that after infestation, a T(H2)-type immune response occurred. Also, major basic protein, nitric oxide, and eotaxin were found in the tissue, and eosinophil cationic protein and eosinophil protein X levels were elevated in sera.

CONCLUSION

These data and in vitro lymphocyte cultures indicate that a T(H2) mechanism plays an important role in the inflammatory infiltrate produced by the anchorage of parasites in the gastrointestinal wall.