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

The role of helminths in the development of non-communicable diseases

Non-communicable diseases (NCDs) like cardiovascular disease, chronic respiratory diseases, cancers, diabetes, and neuropsychiatric diseases cause significant global morbidity and mortality which disproportionately affect those living in low resource regions including low- and middle-income countries (LMICs). In order to reduce NCD morbidity and mortality in LMIC it is imperative to understand risk factors associated with the development of NCDs. Certain infections are known risk factors for many NCDs. Several parasitic helminth infections, which occur most commonly in LMICs, have been identified as potential drivers of NCDs in parasite-endemic regions. Though understudied, the impact of helminth infections on the development of NCDs is likely related to helminth-specific factors, including species, developmental stage and disease burden. Mechanical and chemical damage induced by the helminth in combination with pathologic host immune responses contribute to the long-term inflammation that increases risk for NCD development. Robust studies from animal models and human clinical trials are needed to understand the immunologic mechanisms of helminth-induced NCDs. Understanding the complex connection between helminths and NCDs will aid in targeted public health programs to reduce helminth-induced NCDs and reduce the high rates of morbidity that affects millions of people living in parasite-endemic, LMICs globally.

Anisakid Nematodes and Potential Risk of Human Anisakiasis through the Consumption of Hake, Merluccius spp., Sold Fresh in Spanish Supermarkets

Nematode parasite species belonging to the Anisakis simplex complex are the most important cause of human anisakiasis through the consumption of (mainly) undercooked, previously not frozen, or conveniently treated fish. In Spain, the consumption of hake has been recognized as an important source of this parasitosis. With the aim of shedding light on the risk factors that can influence the potential risk of human anisakiasis in Spain through the consumption of fresh hake sold by nationwide supermarket chains, a total of 536 small hake specimens belonging to the species Merluccius bilinearis caught off the Northeast American coasts and Merluccius merluccius caught in the Northeast Atlantic and Mediterranean waters was analysed. Anisakids morphologically identified as Anisakis type I were found as the most prevalent and the most abundant species and were considered the main potential cause of human anisakiasis. Intrinsic and extrinsic factors concerning the hake, such as its origin and season of capture, its size, as well as the days passed between its capture and consumption, should be taken into account to avoid this human parasitosis. It is essential that consumers have access to fish label information which should include, as regulated by the European Commission, traceability data.

Rhino Conjunctivitis and Asthma Among Seafood Processing Workers in Greenland. A Cross-Sectional Study

Introduction: The fishing- and the seafood processing industries are the largest industrial sectors in Greenland. Despite this, only a few cases of occupational diseases in this industry have been reported to the Danish Labor Market Insurance. Occupational asthma and allergy are well-known occupational diseases in the seafood processing industry worldwide and underreporting of occupational diseases in Greenland is suspected.

Objective: The aim of the current study was to examine the associations between job exposures and occupational asthma and rhino conjunctivitis in workers in the Greenlandic seafood processing industry and to compare the prevalence of sensitization by type and degree of exposure to snow crab, shrimp, fish, and the fish parasite, Anisakis simplex.

Methods: Data from 382 Greenlandic seafood processing workers were collected during 2016–2018. Data included questionnaire answers, lung function measurements, skin prick tests, and blood samples with ImmunoCAP. For all analyses, p < 0.05 was considered the level of significance.

Results: 5.5% of the workers had occupational asthma and 4.6% had occupational rhino conjunctivitis. A large proportion of the workers were sensitized to allergens specific to the workplace; 18.1% to snow crab, 13.6% to shrimp, 1.4% to fish, and 32.6% to the fish parasite, A. simplex. We found a dose-response relationship between the risk of being sensitized to snow crab and A. simplex and years of exposure to the allergens in the seafood processing industry.

Conclusion: This study showed that a considerable proportion of workers in the Greenlandic seafood processing industry had occupational asthma and rhino conjunctivitis. Additionally, the study showed high sensitization levels toward snow crab, shrimp, and the fish parasite, A. simplex. This supports the hypothesis of a considerable degree of underreporting of occupational allergic airway disease in the Greenlandic seafood processing industry. Prospectively, it is important to inform workers, leaders, and health care professionals of the health problems and the law on worker's compensation, and to initiate preventive actions at factory and trawler level.

Anisakis, Something Is Moving inside the Fish

The first case of human infection by a species of the Anisakidae family was reported more than 60 years ago. Over the last 20 years, Anisakis has become a highly studied parasite, not only for its parasitism, but also for its role as an inducer of allergic reactions. Several studies have indicated that the pathological changes occurring within the gastrointestinal tract during infection with Anisakis simplex are the combined result of the direct action of the larvae invading the tissue and the complex interaction between the host’s immune system and the parasite. Although the most commonly described pathologies are digestive, urticaria/angioedema and anaphylaxis, occupational asthma and arthritis have been seldom described. This paper is a narrative of the immune-mediated reaction induced by this parasite over the course of the last two decades.

Anisakis pegreffii Extract Induces Airway Inflammation with Airway Remodeling in a Murine Model System

Exposure of the respiratory system to the Anisakis pegreffii L3 crude extract (AE) induces airway inflammation; however, the mechanism underlying this inflammatory response remains unknown. AE contains allergens that promote allergic inflammation; exposure to AE may potentially lead to asthma. In this study, we aimed to establish a murine model to assess the effects of AE on characteristic features of chronic asthma, including airway hypersensitivity (AHR), airway inflammation, and airway remodeling. Mice were sensitized for five consecutive days each week for 4 weeks. AHR, lung inflammation, and airway remodeling were evaluated 24 h after the last exposure. Lung inflammation and airway remodeling were assessed from the bronchoalveolar lavage fluid (BALF). To confirm the immune response in the lungs, changes in gene expression in the lung tissue were assessed with reverse transcription-quantitative PCR. The levels of IgE, IgG1, and IgG2a in blood and cytokine levels in the BALF, splenocyte, and lung lymph node (LLN) culture supernatant were measured with ELISA. An increase in AHR was prominently observed in AE-exposed mice. Epithelial proliferation and infiltration of inflammatory cells were observed in the BALF and lung tissue sections. Collagen deposition was detected in lung tissues. AE exposure increased IL-4, IL-5, and IL-13 expression in the lung, as well as the levels of antibodies specific to AE. IL-4, IL-5, and IL-13 were upregulated only in LLN. These findings indicate that an increase in IL-4+ CD4+ T cells in the LLN and splenocyte resulted in increased Th2 response to AE exposure. Exposure of the respiratory system to AE resulted in an increased allergen-induced Th2 inflammatory response and AHR through accumulation of inflammatory and IL-4+ CD4+ T cells and collagen deposition. It was confirmed that A. pegreffii plays an essential role in causing asthma in mouse models and has the potential to cause similar effects in humans.

Biology, Epidemiology, Clinical Features, Diagnosis, and Treatment of Selected Fish-borne Parasitic Zoonoses

Fish-borne parasites have been part of the global landscape of food-borne zoonotic diseases for many decades and are often endemic in certain regions of the world. The past 20 years or so have seen the expansion of the range of fish-borne parasitic zoonoses to new geographic regions leading to a substantial public health burden. In this article, we summarize current knowledge about the biology, epidemiology, clinical characteristics, diagnosis, treatment and control of selected fish-borne helminthic diseases caused by parasitic roundworm (Anisakis), tapeworm (Dibothriocephalus), and fluke (Metagonimus). Humans acquire infection via consumption of raw or improperly cooked fish or fish products. The burden from these diseases is caused by morbidity rather than mortality. Infected patients may present with mild to severe gastrointestinal (eg, abdominal pain, diarrhea, and indigestion) or allergic manifestations. Patients are often admitted to the hospital or clinic with acute symptoms and no prior health problems and no travel history. Diagnosis is often established based on the detection of the diagnostic parasite stages (eg, eggs or tapeworm segments) in the patient's feces. Sometimes imaging is required to exclude other causes and avoid unnecessary surgery. Dibothriocephalus and Metagonimus are mainly treated with praziquantel. Extraction of adult Dibothriocephalus or Anisakis larvae from the bowel ensures complete elimination of the parasites and prevents a relapse of infection. The development and implementation of more efficient food safety and public health strategies to reduce the burden of zoonotic diseases attributable to fish-borne parasites is highly desirable.

Anisakiasis and Anisakis: An underdiagnosed emerging disease and its main etiological agents

Anisakiasis or anisakiosis is a human parasitic infection caused by the third-stage larvae (L3) of nematodes of the genus Anisakis, although the term is also used in medical literature for the much less frequent (<3% of cases) infection by L3 of other genera of anisakids, particularly Pseudoterranova. These parasites have a marine lifecycle. Humans are infected by the L3 through ingesting of fish and squid, the intermediate/paratenic hosts. The live larvae generally penetrate the wall of the stomach or intestine causing, among other symptoms, intense pain or allergic symptoms. These are emerging, cosmopolite illnesses. Diagnosis and treatment is usually by endoscopy and extraction and identification of the larvae. Allergic forms are usually diagnosed by prick-test and/or allergen-specific IgE detection and treated with a suitable anti-allergy treatment. The patient is also warned against further consumption of marine fish or squid, as these may be infected with Anisakis. The most common method of prevention is thermal treatment of the entire fish or squid prior to consumption (>60 °C, >1 min or - 20 °C, >24 h). Useful measures for the control of anisakiasis would be to establish a national register of cases, to initiate educational campaigns for the general public and consciousness-raising and training campaigns for health professionals. These would be complemented by control measures for the relevant sectors of the economy: fish operators, fish farming, fishermen, fishmongers, fish industry and catering facilities. Possible genetic predisposition for allergy to Anisakis and the possible relationship between anisakiasis and cancer would also require further investigation.

It's a wormy world: Meta-analysis reveals several decades of change in the global abundance of the parasitic nematodes Anisakis spp. and Pseudoterranova spp. in marine fishes and invertebrates

The Anthropocene has brought substantial change to ocean ecosystems, but whether this age will bring more or less marine disease is unknown. In recent years, the accelerating tempo of epizootic and zoonotic disease events has made it seem as if disease is on the rise. Is this apparent increase in disease due to increased observation and sampling effort, or to an actual rise in the abundance of parasites and pathogens? We examined the literature to track long-term change in the abundance of two parasitic nematode genera with zoonotic potential: Anisakis spp. and Pseudoterranova spp. These anisakid nematodes cause the disease anisakidosis and are transmitted to humans in undercooked and raw marine seafood. A total of 123 papers published between 1967 and 2017 met our criteria for inclusion, from which we extracted 755 host-parasite-location-year combinations. Of these, 69.7% concerned Anisakis spp. and 30.3% focused on Pseudoterranova spp. Meta-regression revealed an increase in Anisakis spp. abundance (average number of worms/fish) over a 53 year period from 1962 to 2015 and no significant change in Pseudoterranova spp. abundance over a 37 year period from 1978 to 2015. Standardizing changes to the period of 1978-2015, so that results are comparable between genera, we detected a significant 283-fold increase in Anisakis spp. abundance and no change in the abundance of Pseudoterranova spp. This increase in Anisakis spp. abundance may have implications for human health, marine mammal health, and fisheries profitability.

Anisakis Sensitization in the Croatian fish processing workers: Behavioral instead of occupational risk factors?

We undertook the first study systematically evaluating the risk of Anisakis-sensitization in Croatian fish-processing workers and potential genetic susceptibility to anisakiasis. Anti-Anisakis IgE seroprevalence and risk factors for 600 employees of Croatian fish processing facilities and 466 blood donor controls, were assessed by indirect ELISA targeted with: recombinant Ani s 1 and Ani s 7 allergens, an Anisakis crude extract, the commercial ImmunoCAP kit, and questionnaires. Genetic susceptibility to anisakiasis was evaluated by genotypisation of human leukocytes alleles (HLA). Anti-Anisakis seropositive and a fraction of negative subjects were also assessed by ELISA and Western Blot (WB) for IgG seroprevalence to Trichinella spp. Overall, the observed anti-Anisakis seroprevalence inferred by indirect ELISA was significantly higher in fish processing workers (1.8%, 95% CI 0.9–3.3%) compared to the controls (0%, 0–0.8%). Seven out of 11 Ani s 1 and Ani s 7-positives and none of selected 65 negative sera, tested positive on whole-Anisakis extract (ImmunoCAP), whereas Anisakis crude extract ELISA detected 3.9% (2.4–6.0%) seropositives in fish processing workers, three (14%) of which showed IgE reactivity to milk proteins. The highest risk associated with Anisakis-sensitization among workers was fishing in the free time, rather than any of attributes related to the occupational exposure. Although no association was observed between anti-Anisakis seropositivity and wearing gloves or protective goggles, the majority of workers (92%) wore protective gloves, minimizing the risk for Anisakis sensitization via skin contact. Six HLA alleles within DRB1 gene were significantly associated with seropositivity under dominant, allelic or recessive models. All sera confirmed negative for anti-Trichinella spp. IgG. The study exhaustively covered almost all marine fish processing workers in Croatia, reflecting real-time Anisakis sensitization status within the industry, already under the influence of wide array of allergens.

Anisakiasis is a human disease caused by ingestion of live Anisakis spp. larvae by raw seafood. Fish processing and aquaculture workers (approximately 60 million people world-wide) are at occupational risk of becoming sensitized to Anisakis. This is the first study systematically evaluating the risk of Anisakis-sensitization in Croatian fish-processing workers and potential genetic susceptibility to anisakiasis in the analysed population. Observed seroprevalence was significantly higher in fish processing workers (1.8%) compared to the controls (0%). Surprisingly, the highest risk associated with Anisakis-sensitization among workers was fishing in their free time, rather than any of attributes related to the occupational exposure. While no association was observed between anti-Anisakis seropositivity and wearing gloves or protective goggles, the majority of workers (92%) wore protective gloves, minimizing the risk for Anisakis sensitization via skin contact. Additionally, seroprevalence to another important food-borne helminth, Trichinella spp. assessed in all Anisakis-positive subjects showed to be negative. Almost all marine fish processing workers in Croatia were part of this research, reflecting real-time Anisakis-sensitization status within the industry. This sets a baseline for the future tracking of sensitization in the sector already under the influence of wide array of allergens.

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.

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.

Excretory/secretory products of anisakid nematodes: biological and pathological roles

Parasites from the family Anisakidae are widely distributed in marine fish populations worldwide and mainly nematodes of the three genera Anisakis, Pseudoterranova and Contracaecum have attracted attention due to their pathogenicity in humans. Their life cycles include invertebrates and fish as intermediate or transport hosts and mammals or birds as final hosts. Human consumption of raw or underprocessed seafood containing third stage larvae of anisakid parasites may elicit a gastrointestinal disease (anisakidosis) and allergic responses. Excretory and secretory (ES) compounds produced by the parasites are assumed to be key players in clinical manifestation of the disease in humans, but the molecules are likely to play a general biological role in invertebrates and lower vertebrates as well. ES products have several functions during infection, e.g. penetration of host tissues and evasion of host immune responses, but are at the same time known to elicit immune responses (including antibody production) both in fish and mammals. ES proteins from anisakid nematodes, in particular Anisakis simplex, are currently applied for diagnostic purposes but recent evidence suggests that they also may have a therapeutic potential in immune-related diseases.

Ecology and genetic structure of zoonotic Anisakis spp. from adriatic commercial fish species

Consumption of raw or thermally inadequately treated fishery products represents a public health risk, with the possibility of propagation of live Anisakis larvae, the causative agent of the zoonotic disease anisakidosis, or anisakiasis. We investigated the population dynamics of Anisakis spp. in commercially important fish-anchovies (Anisakis), sardines (Sardina pilchardus), European hake (Merluccius merluccius), whiting (Merlangius merlangus), chub mackerel (Scomber japonicus), and Atlantic bluefin tuna (Thunnus thynnus)-captured in the main Adriatic Sea fishing ground. We observed a significant difference in the numbers of parasite larvae (1 to 32) in individual hosts and between species, with most fish showing high or very high Anisakis population indices. Phylogenetic analysis confirmed that commercial fish in the Adriatic Sea are parasitized by Anisakis pegreffii (95.95%) and Anisakis simplex sensu stricto (4.05%). The genetic structure of A. pegreffii in demersal, pelagic, and top predator hosts was unstructured, and the highest frequency of haplotype sharing (n = 10) was between demersal and pelagic fish.

Prevalence of sensitization to Anisakis simplex among professionally exposed populations in Sicily

Anisakis simplex (AS) is a cause of allergic sensitization and potential occupational risk is suggested in fishermen and workers assigned to fish processing and sale. A cross-sectional study was conducted in order to assess possible health effects of occupational exposure to AS in workers recruited from western Sicily fisheries sector. Social, demographic, and occupation-related data were collected. Serum total immunoglobulin E (IgE) and specific IgE levels to AS (threshold >0.35 kU/L) were determined by an fluoroimmunoassay technique. Ninety-four subjects with potential occupational exposure (fishmongers, fishermen, fish industry employees) were recruited. Specific AS IgEs were detected in 20.2% of the study population. AS IgE seroprevalence was elevated 6.7-fold (p = .03) among fishermen/sailors compared with fish industry workers. The study suggested the importance to adopt specific prevention strategies against exposure to AS in the occupational setting.

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.

Seafood workers and respiratory disease: an update

PURPOSE OF REVIEW

This review focuses on seafood workers engaged in harvesting, processing and food preparation. These groups are increasingly at risk of developing occupational allergy and respiratory disease as a result of seafood handling and processing activities. This review provides an update of a previous review conducted a decade ago.

RECENT FINDINGS

Exposure characterization studies have demonstrated that aerosolization of seafood (muscle, visceral organs, skin/mucin) during canning and fishmeal operations result in highly variable levels of airborne particulate (0.001-11.293 mg/m3) and allergens (0.001-75.748 ug/m3). Occupational asthma is more commonly associated with shellfish (4-36%) than with bony fish (2-8%). Other seafood-associated biological (Anisakis) and chemical agents (protease enzymes, toxins and preservatives) have also been implicated. Atopy, smoking and level of exposure to allergens are significant risk factors for sensitization and the development of occupational asthma. Molecular studies of the allergens suggest that aside from tropomyosin and parvalbumin, other as yet uncharacterized allergens are important.

SUMMARY

Future research needs to focus on detailed characterization of allergens in order to standardize exposure assessment techniques, which are key to assessing the impact of interventions. The clinical relevance of agents such as serine proteases and endotoxins in causing asthma through nonallergic mechanisms needs further epidemiological investigation.

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.

Occupational allergy and asthma among salt water fish processing workers

BACKGROUND

Fish processing is a common economic activity in Southern Africa. The aim of this study was to determine the prevalence and host determinants of allergic symptoms, allergic sensitization, bronchial hyper-responsiveness and asthma among workers processing saltwater fish.

METHODS

A cross-sectional study was conducted on 594 currently employed workers in two processing plants involved in pilchard canning and fishmeal processing. A modified European Community Respiratory Health Survey (ECRHS) questionnaire was used. Skin prick tests (SPT) used extracts of common airborne allergens, fresh fish (pilchard, anchovy, maasbanker, mackerel, red eye) and fishmeal. Spirometry and methacholine challenge tests (MCTs; tidal breathing method) used ATS guidelines.

RESULTS

Work-related ocular-nasal symptoms (26%) were more common than asthma symptoms (16%). The prevalence of atopy was 36%, while 7% were sensitized to fish species and 26% had NSBH (PC(20) < or = 8 mg/ml or > or =12% increase in FEV(1) post-bronchodilator). The prevalence of probable occupational asthma was 1.8% and fish allergic rhino-conjunctivitis 2.6%. Women were more likely to report work-related asthma symptoms (OR = 1.94) and have NSBH (OR = 3.09), while men were more likely to be sensitized to fish (OR = 2.06) and have airway obstruction (OR = 4.17). Atopy (OR = 3.16) and current smoking (OR = 2.37), but not habitual seafood consumption were associated with sensitization to fish.

CONCLUSIONS

Based on comparison with previous published studies, the prevalence of occupational asthma to salt water fish is lower than due to shellfish. The gendered distribution of work and exposures in fish processing operations together with atopy and cigarette smoking are important determinants of occupational allergy and asthma.

Anisakis simplex: from obscure infectious worm to inducer of immune hypersensitivity

Infection of humans with the nematode worm parasite Anisakis simplex was first described in the 1960s in association with the consumption of raw or undercooked fish. During the 1990s it was realized that even the ingestion of dead worms in food fish can cause severe hypersensitivity reactions, that these may be more prevalent than infection itself, and that this outcome could be associated with food preparations previously considered safe. Not only may allergic symptoms arise from infection by the parasites ("gastroallergic anisakiasis"), but true anaphylactic reactions can also occur following exposure to allergens from dead worms by food-borne, airborne, or skin contact routes. This review discusses A. simplex pathogenesis in humans, covering immune hypersensitivity reactions both in the context of a living infection and in terms of exposure to its allergens by other routes. Over the last 20 years, several studies have concentrated on A. simplex antigen characterization and innate as well as adaptive immune response to this parasite. Molecular characterization of Anisakis allergens and isolation of their encoding cDNAs is now an active field of research that should provide improved diagnostic tools in addition to tools with which to enhance our understanding of pathogenesis and controversial aspects of A. simplex allergy. We also discuss the potential relevance of parasite products such as allergens, proteinases, and proteinase inhibitors and the activation of basophils, eosinophils, and mast cells in the induction of A. simplex-related immune hypersensitivity states induced by exposure to the parasite, dead or alive.

Anisakis simplex: analysis of expressed sequence tags (ESTs) of third-stage larva

This study analyzed the expressed sequence tags (ESTs) of the third-stage larvae of Anisakis simplex, in an attempt to gain further insight into its genomic expression patterns. An A. simplex cDNA library was constructed using the Uni-ZAP XR expression vector. A total of 493 clones (insert DNA>400 bp) were sequenced out of 580 clones selected randomly from a cDNA library of the A. simplex third-stage larva. After BLAST search analyses, 154 (31.2%) ESTs were found to have very low similarity, or no match at all to any of the proteins and gene sequences in the published databases. Most matched clones (98 clones, 20.0%) were determined to be highly homologous with the genes or proteins of Caenorhabditis elegans. Ten (2.0%) ESTs matched the genes isolated from humans, and 21 (4.3%) ESTs matched with the previously reported A. simplex genes or proteins. Eighty-nine clones (18.0%) matched a total of 14 genera and 17 species of human parasites. These 339 ESTs identified could be grouped into 13 categories: allergens or antigens (4.1%), growth- and cell division-related proteins (3.2%), heat shock proteins or molecular chaperones (1.8%), membrane proteins (5.6%), metabolism-associated proteins (24.2%), mitochondrial proteins (9.4%), nuclear proteins (2.4%), proteases and protease inhibitors (3.5%), signal transduction proteins (2.4%), structural proteins (7.4%), transcription and translation machinery-associated proteins (20.1%), transporters and receptor proteins (3.8%), and other protein types (12.1%). The genetic information of Anisakis determined in this study might prove to be quite helpful in elucidating the pathogenetic mechanisms of anisakidosis, and might be useful in the development of therapeutic reagents specific to anisakidosis.

Larval anisakid infections of some tropical fish species from north-west Australia

Despite the commercial and zoonotic importance of larval anisakid infestations of teleosts, their distribution among Australia's diverse marine fish fauna is poorly understood. A preliminary survey of Australia's tropical north-west revealed a generally high prevalence of larval anisakids representing four genera (Anisakis, Terranova, Thynnascaris and Raphidascaris) among only seven fish species. The potential impact of high larval anisakid infections on both the health of recreational fishermen and aquaculture environments is discussed.

Immune reactions and allergy in experimental anisakiasis

The third-stage larvae (L3) of the parasitic nematode, Anisakis simplex, have been implicated in the induction of hyperimmune allergic reactions in orally infected humans. In this work, we have conducted a review of an investigation into immune reactions occurring in animals experimentally infected with A. simplex L3. The patterns of serum antibody productions in the experimental animals against excretory-secretory products (ESP) of A. simplex L3 contributed to our current knowledge regarding specific humoral immune reactions in humans. In our review, we were able to determine that L3 infection of experimental animals may constitute a good model system for further exploration of immune mechanisms and allergy in anisakiasis of humans.

Fish-borne parasitic zoonoses: status and issues

The fish-borne parasitic zoonoses have been limited for the most part to populations living in low- and middle-income countries, but the geographical limits and populations at risk are expanding because of growing international markets, improved transportation systems, and demographic changes such as population movements. While many in developed countries will recognize meat-borne zoonoses such as trichinellosis and cysticercosis, far fewer are acquainted with the fish-borne parasitic zoonoses which are mostly helminthic diseases caused by trematodes, cestodes and nematodes. Yet these zoonoses are responsible for large numbers of human infections around the world. The list of potential fish-borne parasitic zoonoses is quite large. However, in this review, emphasis has been placed on liver fluke diseases such as clonorchiasis, opisthorchiasis and metorchiasis, as well as on intestinal trematodiasis (the heterophyids and echinostomes), anisakiasis (due to Anisakis simplex larvae), and diphyllobothriasis. The life cycles, distributions, epidemiology, clinical aspects, and, importantly, the research needed for improved risk assessments, clinical management and prevention and control of these important parasitic diseases are reviewed.

Sensitization to Anisakis simplex s.l. in a healthy population

The main objective of this study was to determine the degree of sensitization to Anisakis simplex s.l. in healthy population. Using the determination of specific IgE, we studied the seroprevalence against A. simplex s.l. in blood donors selected at random in the region of Antequera (Southern Spain). We detected 22.1%. The immunoblotting technique revealed a band of approximately 60 kDa in the serum of individuals who also exhibited high values of specific IgE against A. simplex s.l. This band would be useful for diagnosis.

Anisakis simplex allergy: a murine model of anaphylaxis induced by parasitic proteins displays a mixed Th1/Th2 pattern

The study of the singular hypersensitivity reactions to Anisakis simplex (A.s) proteins, may help us to undestand many of the unknown immune interactions between helmiths infections and allergy. We have developed a murine model of allergy to A. simplex, that mimics human A. simplex allergy to study the specific aspects of anaphylaxis induced by parasites. Male C3H/HeJ mice were intraperitoneally sensitized to A. simplex. Mice were then intravenous or orally challenged with A. simplex. Antigen-specific immunoglobulins, polyclonal IgE, anaphylactic symptoms, plasma histamine levels and cytokine profiles were determined. Comparative IgE immunoblot analyses were also performed. Specific IgE, IgG(1) and IgG(2a) were detected in sensitized mice since week 3. Polyclonal IgE raised and peaked with different kinetics. Intravenous A. simplex challenge produced anaphylaxis in mice, accompanied by plasma histamine release. Oral A. simplex challenge in similarly sensitized mice did not caused symptoms nor histamine release. Numerous A. simplex allergens were recognized by sensitized mouse sera, some of them similar to human serum. The A. simplex stimulated splenocytes released IL-10, IFN-gamma, IL-4, IL-13 and IL-5. We describe a new animal model of anaphylaxis. It exhibits characteristics of type I hypersensitivity reactions to Anisakis simplex similar to those observed in allergic humans. Different responses to i.v. or oral A. simplex challenges emerged, which did not reflect a window tolerization period. The cytokine profile developed (mixed Th(1)/Th(2) pattern) differed from the observed in classical models of anaphylaxis or allergy to food antigens. This model may permit to investigate the peculiar allergic reactions to parasitic proteins.

Gingivostomatitis after eating fish parasitized by Anisakis simplex: a case report

Anisakis simplex (AS) is a nematode that may be encountered as a parasite in various kinds of seafood. Human beings may accidentally acquire AS larvae by eating raw or undercooked seafood. In addition to human parasitization (anisakiasis), this nematode can induce allergic reactions. AS-related diseases are frequent, especially in those countries with a high level of fish consumption and with traditions of eating raw or undercooked seafood. To our knowledge, this is the first report of gingivostomatitis secondary to the ingestion of fish with AS parasites.

Occupational seafood allergy: a review

BACKGROUND

Recent years have seen increased levels of production and consumption of seafood, leading to more frequent reporting of allergic reactions in occupational and domestic settings. This review focuses on occupational allergy in the fishing and seafood processing industry.

REVIEW

Workers involved in either manual or automated processing of crabs, prawns, mussels, fish, and fishmeal production are commonly exposed to various constituents of seafood. Aerosolisation of seafood and cooking fluid during processing are potential occupational situations that could result in sensitisation through inhalation. There is great variability of aerosol exposure within and among various jobs with reported allergen concentrations ranging from 0.001 to 5.061(microg/m(3)). Occupational dermal exposure occurs as a result of unprotected handling of seafood and its byproducts. Occupational allergies have been reported in workers exposed to arthropods (crustaceans), molluscs, pisces (bony fish) and other agents derived from seafood. The prevalence of occupational asthma ranges from 7% to 36%, and for occupational protein contact dermatitis, from 3% to 11%. These health outcomes are mainly due to high molecular weight proteins in seafood causing an IgE mediated response. Cross reactivity between various species within a major seafood grouping also occurs. Limited evidence from dose-response relations indicate that development of symptoms is related to duration or intensity of exposure. The evidence for atopy as a risk factor for occupational sensitisation and asthma is supportive, whereas evidence for cigarette smoking is limited. Disruption of the intact skin barrier seems to be an important added risk factor for occupational protein contact dermatitis.

CONCLUSION

The range of allergic disease associated with occupational exposure to crab is well characterised, whereas for other seafood agents the evidence is somewhat limited. There is a need for further epidemiological studies to better characterise this risk. More detailed characterisation of specific protein antigens in aerosols and associated establishment of dose-response relations for acute and chronic exposure to seafood; the respective roles of skin contact and inhalational exposure in allergic sensitisation and cross reactivity; and the contribution of host associated factors in the development of occupational seafood allergies are important areas for future research.