The response of Anisakis simplex (s. s.) to anthelmintics - Specific changes in xenobiotic metabolic processes

Anisakiasis is a parasitic disease transmitted through the consumption of raw or undercooked fish and cephalopods that are infected with larvae of Anisakis simplex (sensu stricto) or Anisakis pegreffii. The purpose of this study was to investigate how A. simplex (s. s.) responds to the influence of anthelmintics such as ivermectin (IVM) and pyrantel (PYR). In vitro experiments were conducted using larvae at two developmental stages of A. simplex (s. s.) (L3 and L4) obtained from Baltic herring (Clupea harengus membras). Larvae were cultured with different concentrations of IVM or PYR (1.56, 3.125, and 6.25 μg/mL) for various durations (3, 6, 9, and 12 h) under anaerobic conditions (37 °C, 5% CO2). The gene expression of actin, ABC transporter, antioxidant enzymes, γ-aminobutyric acid receptors, and nicotinic acetylcholine receptors, as well as the oxidative status were analyzed. The results showed that A. simplex (s. s.) L3 stage had lower mobility when cultured with PYR compared to IVM. The analysis of relative gene expression revealed significant differences in the mRNA level of ABC transporters after treatment with IVM and PYR, compared to the control group. Similar patterns were observed in the gene expression of antioxidant enzymes in response to both drugs. Furthermore, the total antioxidant capacity (TAC) and glutathione S-transferase (GST) activity were higher in the treatment groups than in the control group. These findings suggest a relationship between the expression of the studied genes, including those related to oxidative metabolism, and the effectiveness of the tested drugs.

[Investigation of Anisakis infections in coastal marine fishes and awareness of anisakiasis control knowledge among residents in Yantai City in 2021]

OBJECTIVE

To investigate the prevalence of Anisakis infections in coastal marine fishes and awareness of anisakiasis control knowledge among local residents in Yantai City, Shandong Province in 2021, so as to provide insights into formulation of anisakiasis control interventions.

METHODS

Marine fishes were purchased from Shunxin Port, Yantai City, Shandong Province in November 2021, and the presence of Anisakis was detected in different species of fishes and different fish sites. The correlations between body length and weight of marine fish and intensity of Anisakis infections were examined using Spearman's rank correlation analysis, and the dietary habits and anisakiasis control knowledge were investigated using questionnaire surveys among local residents.

RESULTS

A total of 201 marine fishes belonging to 20 species were dissected, and Anisakis was detected in 77 marine fishes (38.31%) belonging to 11 species (55.00%), with a mean infection intensity of 45.04 parasites per fish (3 468/77). Spearman's rank correlation analysis revealed that the body length (rs = 0.74, P < 0.05) and weight (rs = 0.79, P < 0.01) of the monkfish correlated positively with the intensity of Anisakis infections, and the body length (rs = 0.68, P < 0.05) of the flatfish correlated positively with the intensity of Anisakis infections, while no correlations were examined between the body length or weight of other marine fishes and the intensity of Anisakis infections. Of all respondents, 53.38% men and 56.67% women did not know anisakiasis control knowledge at all, and there was a significant difference in the proportion of respondents using separate chopping boards for raw and cooked food from different villages (χ2 = 17.89, P < 0.01), while there was an age-specific proportion of respondents with habitats of eating raw or semi-raw seafood (χ2 = 28.27, P < 0.01).

CONCLUSIONS

The prevalence and intensity of Anisakis infections were high in coastal marine fishes in Yantai City in 2021, and the awareness of anisakiasis control knowledge was low among local residents. Intensified health education pertaining to anisakiasis control knowledge is recommended to reduce the risk of Anisakis infections.

A critical review of anisakidosis cases occurring globally

A review was conducted to identify the most common causative agents of anisakidosis, the methods used for identification of the causative agents, and to summarize the sources of infection, and patients' demographics. A total of 762 cases (409 articles, inclusive of all languages) were found between 1965 and 2022. The age range was 7 months to 85 years old. Out of the 34 countries, Japan, Spain, and South Korea stood out with the highest number of published human cases of anisakidosis, respectively. This raises the question: Why are there few to no reports of anisakidosis cases in other countries, such as Indonesia and Vietnam, where seafood consumption is notably high? Other than the gastrointestinal tract, parasites were frequently found in internal organs such as liver, spleen, pancreas, lung, hiatal and epigastric hernia, and tonsils. There are also reports of the worm being excreted through the nose, rectum, and mouth. Symptoms included sore throat, tumor, bleeding, gastric/epigastric/abdominal/substernal/lower back/testicular pain, nausea, anorexia, vomiting, diarrhea, constipation, intestinal obstruction, intussusception, blood in feces, hematochezia, anemia, and respiratory arrest. These appeared either immediately or up to 2 months after consuming raw/undercooked seafood and lasting up to 10 years. Anisakidosis commonly mimicked symptoms of cancer, pancreatitis, type I/II Kounis syndrome, intussusception, Crohn's disease, ovarian cysts, intestinal endometriosis, epigastralgia, gastritis, gastroesophageal reflux disease, hernia, intestinal obstruction, peritonitis, and appendicitis. In these cases, it was only after surgery that it was found these symptoms/conditions were caused by anisakids. A range of not only mainly marine but also freshwater fish/shellfish were reported as source of infection. There were several reports of infection with >1 nematode (up to >200), more than one species of anisakids in the same patient, and the presence of L4/adult nematodes. The severity of symptoms did not relate to the number of parasites. The number of anisakidosis cases is grossly underestimated globally. Using erroneous taxonomic terms, assumptions, and identifying the parasite as Anisakis (based solely on the Y-shaped lateral cord in crossed section of the parasite) are still common. The Y-shaped lateral cord is not unique to Anisakis spp. Acquiring a history of ingesting raw/undercooked fish/seafood can be a clue to the diagnosis of the condition. This review emphasizes the following key points: insufficient awareness of fish parasites among medical professionals, seafood handlers, and policy makers; limited availability of effective diagnostic methodologies; and inadequate clinical information for optimizing the management of anisakidosis in numerous regions worldwide.

A case of chronic gastric anisakiasis coexisting with early gastric cancer

Background

Anisakiasis is a parasitic disease caused by the consumption of raw or undercooked fish that is infected with Anisakis third-stage larvae. In countries, such as Japan, Italy, and Spain, where people have a custom of eating raw or marinated fish, anisakiasis is a common infection. Although anisakiasis has been reported in the gastrointestinal tract in several countries, reports of anisakiasis accompanied by cancer are rare.

Case presentation

We present the rare case of a 40-year-old male patient with anisakiasis coexisting with mucosal gastric cancer. Submucosal gastric cancer was suspected on gastric endoscopy and endoscopic ultrasonography. After laparoscopic distal gastrectomy, granulomatous inflammation with Anisakis larvae in the submucosa was pathologically revealed beneath mucosal tubular adenocarcinoma. Histological and immunohistochemical investigation showed cancer cells as intestinal absorptive-type cells that did not produce mucin.

Conclusion

Anisakis larvae could have invaded the cancer cells selectively because of the lack of mucin in the cancerous epithelium. Anisakiasis coexisting with cancer is considered reasonable rather than coincidental. In cancer with anisakiasis, preoperative diagnosis may be difficult because anisakiasis leads to morphological changes in the cancer.

Anisakis infection in anchovies (Engraulis encrasicolus) from Iberian waters, southwestern Europe: Post-mortem larval migration

The Anisakis larvae presence in fish for human consumption is a health risk that needs to be monitored. The anchovy is a fish that is highly appreciated by consumers and that can harbour Anisakis. It is thus necessary to periodically evaluate the presence of anisakid larvae in them. So, anchovies from Iberian Peninsula coasts were analysed. Fish examination for macroscopic nematodes showed L3s of both Anisakis type I and Hysterothylacium aduncum. The Anisakis prevalence varies with the catching area and the fish size. The muscle prevalence was 7.45% (mean intensity 1.75; range 1-5). Molecular analysis showed 110 A. simplex s.s. (17 in muscle), 22 A. pegreffii (3) and 7 hybrid genotype individuals (1). Considering that most of the Iberian Peninsula coasts are a sympatry area between these two Anisakis species, it has been observed that A. simplex s.s./A. pegreffii ratio increases from south to north in a clockwise direction. Also, 19 larvae were detected on the fish surface from the Bay of Biscay, indicating the ability of these larvae to migrate after the fish death. The A. simplex s.s./A. pegreffii larvae proportion found on the anchovy surface is similar to the found in viscera and lower than in muscle, suggesting that most of the larvae migrating to the surface must have come from the visceral package. This confirms the importance of removing fish viscera immediately after capture, for those fish species where this is possible. As both species cause anisakiasis/anisakidosis, these data show a real risk to human health, especially in dishes highly prized in Mediterranean countries prepared with raw or semi-raw anchovies.

Anisakidae parasites in frozen fish fillets intended for human consumption

INTRODUCTION

Anisakiasis is a human parasitic disease caused by the consumption of raw fish or shellfish containing larvae of the Anisakidae family. It is currently considered an emerging disease of public health interest.

OBJECTIVE

To identify the presence of larvae of the Anisakidae family in samples of frozen raw fish fillets intended for human consumption in markets in Medellín and its metropolitan area in Antioquia, Colombia.

MATERIALS AND METHODS

A cross-sectional study was carried out, in which larvae of the Anisakidae family were detected and identified in frozen raw fish fillets from three representative markets in Medellín and its metropolitan area. A total of 384 ready for consumption fillets were analyzed (197 sawfish, 137 salmon, 37 tuna, and 13 hake), using the pressing and ultraviolet light method. Taxonomic keys were used to identify the collected parasites and to establish its genus. Conventional PCR and Sanger sequencing was performed to determine the species.

RESULTS

Four larvae were found in 4 of the 384 (1.04%) fillets (CI95% 1.04 ± 1.01%). The species of fish in which the larvae were found was sawfish (Scomberomorus spp.) and the genus and species of the larvae was established as Anisakis pegreffii.

CONCLUSIONS

According to the study, the presence of Anisakis parasites in frozen raw fish fillets in the influence area is evident.

Infection process, viability and establishment of Anisakis simplex s.l. L3 in farmed fish; A histopathological study in gilthead seabream

Anisakis spp. (Nematoda, Anisakidae) are parasites known by their economic and health impacts, as their L3 larval stages infect a variety of fish species, many of them commercial species, sometimes causing zoonotic episodes due to consumption of raw or undercooked fish. The aim of this study is to determine the infection process and the potential impact of A. simplex s.l. L3 on gilthead seabream (Sparus aurata L.), one of the most important fish species in Mediterranean aquaculture, by periodic histological monitoring of the infection process. For this, fish were experimentally infected with A. simplex s.l. L3 and periodically analysed for L3 larvae, collecting samples at different time points (hours post ingestion, hpi): 3, 6, 12, 18, 24, 36, 48, 72, 96, 120, 144, 168 and 192, up to 6 months post infection (mpi). All samples were observed under a stereomicroscope and later fixed for histological examination. A. simplex s.l. L3 were only found on the visceral surface and mesenteric tissue, but never free or encapsulated in muscle. Chronological events were found to occur faster than those reported in previous studies. They were first observed 6 hpi in the coelomic cavity, being present up to 48 hpi. While the earliest evidence of fibrocytes surrounding A. simplex s.l. L3 larvae were observed at 18 hpi, complete spiral encapsulation occurred by 72 hpi. Alive parasites were observed up to 6 mpi. Although the infection of gilthead seabream by Anisakis spp. larvae is feasible, it seems unlikely, especially in aquaculture given the hygienically controlled feeding systems. In the event of infection, the transmission would be unlikely due to the poor condition in which specimens of Anisakis spp. are found. Furthermore, since no larvae were detected in the fish's muscle, human infection seems improbable.

Anisakis spp, DNA detection in paraffin-embedded tissue biopsies recovered from patients with gastritis using real-time PCR in Bushehr, Persian Gulf, Iran

Anisakiasis is a zoonotic fish-born parasitic disease caused by anisakid nematodes. Paraffin-embedded blocks containing biopsy samples taken from patients suffering gastritis with unknown causes were investigated by real-time PCR, in the Bushehr region, Iran; where human anisakiasis has not been reported, so far. A total of 50 paraffin-embedded blocks were randomly selected from 250 archived blocks of the patients with gastritis. A SYBER green-based real-time PCR targeting the ITS1 region was developed for the identification of Anisakis genus. An 86 bp partial fragment of the Anisakis spp. ITS1 gene was amplified successfully. A total of 3 out of 50 samples (6 %) had positive amplification in the samples and their pathology reports showed a significant finding of moderate chronic gastritis with or without ulcers. In conclusion, the developed qPCR could be used for detecting Anisakis spp. larval DNA in human biopsy blocks. This study showed the hidden human cases of anisakiasis in the Bushehr for the first time.

Ascaridoid nematodes infecting commercially important marine fish and squid species from Bangladesh waters in the Bay of Bengal

Parasitic ascaridoid nematodes occur in a wide range of marine organisms across the globe. Some species of the anisakid family (Ascaridoidea: Anisakidae) can cause gastrointestinal disease in humans (i. e. anisakidosis). Despite their importance as potentially hazardous parasites, the occurrence and infection characteristics of ascaridoids are still poorly known from many host species and geographical areas. This study investigated the diversity and infection levels of ascaridoid parasites in various commercial fish and squid host species off Bangladesh. Fish and squid specimens were visually inspected for nematodes using the UV-press method. Nematodes were assigned to genus level based on morphology and identified by sequence analyses of the entire ITS region and partial 28S rDNA and mtDNA cox2 genes. Third-stage larvae (L3) of Anisakis typica occurred at low prevalence (P = 10% and 8%, respectively) in the viscera of Selar crumenophthalmus and Trichiurus lepturus, while Hysterothylacium amoyense occurred in the viscera of Sardinella fimbriata (P = 1%) and the viscera and muscle of Harpadon nehereus (P = 32%) and T. lepturus (P = 76%). Lappetascaris sp. Type A L3 occurred in the mantle of the squid Uroteuthis duvaucelii (P = 11%). Anisakis and Lappetascaris species, and H. amoyense were firstly identified in the Bay of Bengal. The potentially zoonotic A. typica was only found in fish viscera. Hysterothylacium amoyense and Lappetascaris sp., both generally regarded as non-zoonotic, occurred at low prevalence in the muscle or mantle of fish or squid, respectively. Since consumption of raw or lightly processed seafood seems to be rare in Bangladesh, the risk of acquiring anisakidosis from consuming fishery products from off Bangladesh appears to be low. Due to its reddish appearance, the visual presence of H. amoyense larvae in fish flesh may represent a food quality issue.

Prevalence and molecular identification of zoonotic Anisakis and Pseudoterranova species in fish destined to human consumption in Chile

Zoonotic larvae of the family Anisakidae found in several fish species represent a serious risk in public health since they may cause food-borne anisakidosis in humans. Chile has culinary preferences including eating raw fish in many traditional preparations. In the present study, a total of 180 fish specimens representing three different fish species, i.e., Chilean hake (Merluccius gayi), snoek (Thyrsites atun), and sea bream (Brama australis), were caught at central coast of Chile. Parasitological examination was performed on musculature and abdominal cavity for subsequent extraction and quantification of anisakid larvae. Estimation of infection parameters, such as prevalence, was performed indicating 100% (CI: 0.94-1.0) prevalence of anisakid L3 in Chilean hakes and snoeks. Moreover, sea breams reached a prevalence of 35% (CI: 0.23-0.48). Prevalence of anisakid larvae in muscle was also analyzed showing values of 18.6% (CI: 0.097-0.309) in Chilean hakes, 15% (CI: 0.07-0.26) in snoeks, and 1.7% (CI: 0-0.089) in sea breams. Meanwhile, prevalence of anisakid larvae in internal organs showed highest values for peritoneum (100% and 83.3%) for snoeks and Chilean hakes, respectively, for liver (96.7%) and gonads (86.6%) in Chilean hakes, and for intestine (98.3%) in snoeks. Molecular analysis of collected anisakid L3 unveiled presence of two potentially zoonotic nematode species, i.e., Pseudoterranova cattani and Anisakis pegreffii. P. cattani was found in Chilean hakes and snoeks being the first molecular host species report for Chilean snoeks. Besides, A. pegreffii was also identified in these species being the first molecular report on this regard. These findings are relevant for better understanding of epidemiology of anisakiasis in Chilean coasts and for public health issues considering potential risk of human population due to its culinary preferences in eating raw fish.

Anisakis Allergy: Raising Awareness

INTRODUCTION

Ingestion of Anisakis is a common cause of allergic reactions to seafood in countries in which undercooked/raw seafood is part of gastronomic traditions. Despite current trends for the ingestion of raw/marinated/undercooked fish, the prevalence rate of anisakiasis and allergy to Anisakis is still considered to be low in Portugal. We aimed to review the current pathogenic mechanisms, the clinical and diagnostic approach of Anisakis allergy, and Anisakis-related eviction measures, while raising awareness to this problem.

MATERIAL AND METHODS

Literature search in the MEDLINE and Scopus databases, regarding Anisakis allergy.

CONCLUSION

Assessment of sensitization to Anisakis should be included in the workup study of urticaria/angioedema and anaphylaxis, as there is a rise in consumption of raw and undercooked fish. Ingestion of previously frozen and properly cooked fish appears to be safe for most patients who are allergic to Anisakis.

Molecular identification and epidemiological data of Anisakis spp. (Nematoda: Anisakidae) larvae from Southeastern Pacific Ocean off Peru

The objective of this study is to determine the infection status of nematode larvae and record epidemiological molecular data in commercial fish from the southeast Pacific off the central coast of Peru. Anisakiasis is a fish-borne zoonosis caused by Anisakis larvae, parasites of relevance in the fishery resources that have negative impact on public health. Between January 2012 to December 2014, 345 specimens of four fish species (Trachurus symmetricus murphyi, Scomber japonicus peruanus, Merluccius gayi peruanus and Seriolella violacea) were examined for Anisakis sp. larvae. A total of 997 Anisakis sp. larvae were found in the body cavity of 196 fish (total prevalence 53.7%, total mean intensity 5.08). After morphological analysis, 958 (96.08%) larvae were identified as Type I and 39 (3.92%) as Type II. Specimens were identified by molecular analysis of the mitochondrial cytochrome c oxidase subunit II (cox2) gene, confirming that A. pegreffii is the predominant species and the most important agent of human anisakiasis off the Peru Central Coast. In addition, we revealed the occurrence of A. physeteris (s.l.) in S. japonicus peruanus (P = 18.0%; MI = 2.17).

Therefore, the results obtained in the present study improve the knowledge of the occurrence of Anisakis species in the commercial fish from the Southeastern Pacific Ocean, highlighting the importance of considering a potential hazard for humans and the necessity of further research in other fishes of greater preference by the Peruvian population.

•

Anisakiasis is a fish-borne zoonosis caused by larvae of the nematode Anisakis sp. present in fish.

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The dominant species on the central coast of the Peruvian Sea is A. pegreffii.

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A. physeteris (s.l.) was found parasitizing only one host with a low prevalence.

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Widespread occurrence of Anisakis sp. in wild sea fish.

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.

Molecular and evolutionary basis for survival, its failure, and virulence factors of the zoonotic nematode Anisakis pegreffii

Parasitism is a highly successful life strategy and a driving force in genetic diversity that has evolved many times over. Accidental infections of non-targeted hosts represent an opportunity for lateral host switches and parasite niche expansion. However, if directed toward organisms that are phylogenetically distant from parasite's natural host, such as humans, it may present a dead-end environment where the parasite fails to mature or is even killed by host immunity. One example are nematodes of Anisakidae family, genus Anisakis, that through evolution have lost the ability to propagate in terrestrial hosts, but can survive for a limited time in humans causing anisakiasis. To scrutinize versatility of Anisakis to infect an evolutionary-distant host, we performed transcriptomic profiling of larvae successfully migrating through the rat, a representative model of accidental human infection and compared it to that of larvae infecting an evolutionary-familiar, paratenic host (fish). In a homeothermic accidental host Anisakis upregulated ribosome-related genes, cell division, cuticle constituents, oxidative phosphorylation, in an unsuccessful attempt to molt to the next stage. In contrast, in the paratenic poikilothermic host where metabolic pathways were moderately upregulated or silenced, larvae prepared for dormancy by triggering autophagy and longevity pathways. Identified differences and the modelling of handful of shared transcripts, provide the first insights into evolution of larval nematode virulence, warranting their further investigation as potential drug therapy targets.

Anisakiasis of the Terminal Ileum Removed by Colonoscopy

A 35-year-old Japanese man with no significant medical history presented to the emergency department complaining of abdominal pain, nausea, and vomiting 35 h after ingesting raw horse mackerel, sardines, and tuna. Computed tomography of the abdomen with intravenous contrast revealed significant thickening of the terminal ileum with mild proximal dilatation and moderate ascites. On colonoscopy, an actively moving anisakis larva was discovered in the terminal ileum. The larva was removed with endoscopic forceps. The patient's symptoms resolved quickly following the procedure.

Shotgun Proteomics for L3 and L4 Anisakis simplex Development Stages

Anisakis simplex s.s. is a parasitic nematode that causes anisakiasis in humans. L3 stage larvae, which are present in many fish species and cephalopods all over the globe, might be consumed and develop occasionally into the L4 stage but cannot reproduce. Anisakiasis is an emerging health problem and economic concern. In recent years, proteomic methods have gained greater acceptance among scientists involved in parasitology and food science. According to that, here, we present tandem mass tag (TMT)-based shotgun proteomics to define differences in proteomic composition between L3 and L4 development stages of A. simplex s.s.

Acute Anisakiasis: Pharmacological Evaluation of Various Drugs in an Animal Model

BACKGROUND

The accidental ingestion of the third larval stage of Anisakis can cause acute clinical symptoms, which are relieved via extraction of the larvae. Although this is a highly effective technique, it can only be practiced when the larvae are found in accessible areas of the gastrointestinal tract, and therefore instead the condition has often been treated using various different drugs.

AIMS

This study evaluates the effectiveness of gastric acid secretion inhibitors (omeprazole and ranitidine), gastric mucosal protectants (sucralfate) and anthelmintics (mebendazole and flubendazole) in treating anisakiasis in Wistar rats.

METHODS

Rats were infected with Anisakis-type I larvae and administered the drugs via a gastric probe. Data were recorded regarding the number of live and dead larvae, their location both within the animal and in its feces, and the presence of gastrointestinal lesions. Additionally, gastric pH was measured and histology performed.

RESULTS

While rats in all experimental groups exhibited lesions; those treated with ranitidine and mebendazole showed significantly fewer lesions (50% and 35% of rats exhibited lesions, respectively). Histological examination of the gastric lesions revealed infection-induced changes, but no significant differences were observed between the treated and untreated rats.

CONCLUSIONS

Mebendazole was found to be most efficacious in preventing gastrointestinal lesions, followed by ranitidine, which was the most effective antacid of those studied. Both these drugs could thus be considered as part of the conservative management of anisakiasis.

Anisakis simplex (s.s.) larvae (Nematoda: Anisakidae) hidden in the mantle of European flying squid Todarodes sagittatus (Cephalopoda: Ommastrephidae) in NE Atlantic Ocean: Food safety implications

Few reports exist upon the occurrence and localization of zoonotic anisakid nematodes in T. sagittatus, especially in the mantle of the squid. The occurrence and site of infection of larval anisakids in 98 T. sagittatus caught West off St. Kilda, NE Atlantic Ocean, were investigated. Squids were examined for anisakids using the UV-Press method. In total, 689 nematodes were detected in the viscera and mantle. According to morphology, all the larvae (L₃) were assigned to genus Anisakis. Diagnostic allozymes and mtDNA cox2 sequence analysis permitted to genetically identify all larvae as Anisakis simplex (s.s.) (N = 100). Overall prevalence (P = 81%) and mean intensity (mI = 8.6) of infection with A. simplex are provided. Most of the larvae present in the mantle cavity were embedded in the stomach wall or attached in the outer layer of the stomach and caecum (49%). Over a third of squids (37%) hosted A. simplex (s.s.) larvae in the mantle. A novel schematized representation of larvae distribution in the mantle is provided, showing where they were mostly located. According to the results obtained, the risk of anisakiasis associated with consumption of raw or undercooked T. sagittatus should be considered.

Intestinal anisakiasis with severe intestinal ischemia caused by extraluminal live larvae: a case report

Background

Anisakiasis is a parasitic infection caused by Anisakis worms found in raw fish. Most cases of anisakiasis occur in the stomach and rarely occur in the intestine. It is extremely rare for live larvae to break through the intestine into the mesentery and cause severe intestinal ischemia. Anisakiasis can be treated conservatively, because the larvae will die in approximately 1 week, but, sometimes, a serious condition can arise, as in this case. We report the first case of extraluminal anisakiasis in which a live Anisakis worm caused severe intestinal ischemia.

Case presentation

The patient was a 26-year-old woman who ate squid a week prior. She had abdominal pain and was admitted to our emergency department. On physical examination, abdominal guarding and rebound tenderness were present in her lower abdomen. Contrast-enhanced computed tomography showed ascites, the whirl sign, localized submucosal edema of the intestinal wall, and a dilated small bowel segment with edema. We suspected the strangulated small bowel obstruction based on the CT-scan findings. To rule out the strangulated small bowel obstruction, laparoscopic exploration was performed. Bloody ascites in the pouch of Douglas and severe inflammation in 20 cm of the ileum were observed. An Anisakis larva had perforated the intestinal wall and was found alive in the mesentery. The ileum had developed a high degree of ischemia, so the affected section was resected. Histopathological examination revealed that the Anisakis worm body was in the inflamed mesentery and caused a high degree of ischemia in the intestinal tract. The patient was discharged 9 days after surgery.

Conclusions

A living Anisakis larva punctured the mesentery of the small intestine, resulting in severe intestinal ischemia. As seen in this case, intestinal anisakiasis may cause serious symptoms, and a low threshold for performing diagnostic laparoscopy for the early diagnosis of bowel ischemia secondary to anisakiasis can be useful in determining the definite diagnosis and indications for resection.

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.

Anisakiasis: The Importance of Prevention and the Role of Diet Therapy in Allergic Patients

INTRODUCTION

Anisakiasis is a zoonosis of parasitic origin whose diffusion seems to be continuously increasing.

OBJECTIVE

The aim of this study was to evaluate the benefits of a fish-free diet in patients allergic to Anisakis simplex as well as underlining the importance of awareness and prevention. Furthermore, we aimed to investigate the critical issues related to the spread of anisakiasis in relation to eating habits.

METHODS

Patients were assessed by means of skin prick tests (SPTs) and targeted laboratory testing, with an 18-month-long fish-free diet being recommended in cases of severe sensitization. The degree of awareness about anisakiasis was evaluated from interviews. Patients were subjected to follow-up visits after 18 months.

RESULTS

A total of 70 cases of sensitization to A. simplex were evaluated. The Interview answers highlighted a general state of misinformation among patients and healthy subjects along with a remarkable underestimation of anisakiasis-related risks. An overall lack of care regarding eating habits and diet plans also emerged. In 21 patients affected by severe sensitization, clinical and laboratory evaluations were repeated after 18 months of the subjects being on a fish-free diet. There was a remarkable improvement in serum IgE levels and clinical symptoms.

CONCLUSION

Data analysis proved the need to implement new and more effective awareness-raising and prevention campaigns in order to reduce the incidence of anisakiasis. It is crucial to establish an adequate diet therapy for sensitized patients. Evaluation of cytokine patterns suggests how a polyphenol-rich regime can activate regulatory T cell function and possibly reduce the allergic and inflammatory components of the disease.

Anisakiasis in a Canadian patient with incarcerated epigastric hernia

Anisakiasis is human zoonotic parasitic infection caused by a nematode parasite called Anisakis. This infection is usually reported in Asian countries where consumption of raw seafood is common. Very few cases have been reported in North America. We present the case of a female Canadian patient with an Anisakis larvae in an incarcerated ventral hernia. Cases of Anisakis infections are exceedingly rare in western countries, with very few previous reports describing extra-gastrointestinal cases. Diagnosis is often difficult since the symptoms of anisakiasis are not pathognomonic. As the larvae cannot survive in the body, conservative treatment might be effective in intestinal anisakiasis and surgery is usually performed when complications are encountered. Preventive measures are crucial and include educating the public about the risks of raw fish consumption and the importance of visually inspecting consumed fish and freezing it before ingestion to kill the larvae and prevent the infection.

Eosinophil granuloma due to parasite treated by laparoscopic and endoscopic cooperative surgery: a case report

Background

Gastric eosinophilic granuloma caused by parasitic infection is rare. It is often suspected to be a malignant disease and it is difficult to diagnose. We successfully diagnosed and removed a gastric eosinophilic granuloma using laparoscopic and endoscopic cooperative surgery (LECS).

Case presentation

A 35-year-old woman visited our hospital because of epigastric pain. Upper gastrointestinal endoscopy revealed a 15 mm submucosal tumor (SMT) with changes in the folds, such as enlargement and convergence, located in the greater curvature of the lower gastric body. Computed tomography (CT) showed a dense, nonenhanced area of 15 mm at the same site. SMT was suspected, but undifferentiated cancer could not be excluded. We performed laparoscopic partial gastrectomy using LECS for resection biopsy.

Histopathological examination showed an SMT 8 × 8 × 5 mm in size with an unclear boundary and necrosed insects at the core of the tumor. There was marked eosinophilic infiltration around the area. The diagnosis was gastric granuloma caused by parasitic infection.

Conclusions

It is difficult to differentiate gastric eosinophilic granuloma caused by parasitic infection from malignant disease. In this case, LECS is considered a minimally invasive and useful procedure.

Comparison of risk factors between human intestinal and gastric Anisakiasis

BACKGROUND

Little is known in the difference of host factors between intestinal and gastric anisakiasis. The aim of this study was to investigate the associated factors of intestinal anisakiasis in patient's characteristics and the subsequent variation compared to gastric anisakiasis.

METHODS

At St. Luke's International Hospital in Tokyo, Japan, a retrospective cohort study was conducted from April 2004 to June 2017. All adult patients who were clinically diagnosed as anisakiasis based on Computed Tomography (CT) scan or endoscopy were included, and anti-Anisakis antibodies (IgG and IgA) were measured for serological validation of anisakiasis, strengthen the diagnosis. Anisakiasis was categorized as either intestinal or gastric depending on its affected site. We compared patients' demographics, social history, and physical and laboratory findings between those with intestinal and gastric anisakiasis by bivariate analyses, followed by multivariate analyses.

RESULTS

A total of 302 patients were included in this study, where the mean age (SD) was 46.5 (14.4) and 66.6% were male. Ninety-two patients (30.5%) had intestinal anisakiasis. Multivariate regression revealed that patients with intestinal anisakiasis were more 45 years old or older (odds ratio (OR) 3.45, 95% confidence interval (CI): 1.53-7.69), male (OR 2.70, 95% CI: 1.20-6.25) and regular alcohol drinker. In terms of the physical and laboratory findings, patients with intestinal anisakiasis had greater heart rate (OR 2.86, 95% CI: 1.33-6.25), higher total protein (OR 2.86, 95% CI: 1.16-6.67), and higher C-reactive protein (CRP) (OR 11.1, 95% CI: 3.03-33.3).

CONCLUSIONS

Older males who were regular alcohol drinkers were associated with intestinal anisakiasis, and often heart rate, total protein, and CRP were elevated compared to those of patients with gastric anisakiasis.

Clinical and Endoscopic Features of Colonic Anisakiasis in Korea

To analyze the clinical and endoscopic features of colonic anisakiasis. A retrospective chart review of 20 patients with colonic anisakiasis, who were diagnosed by colonoscopy at 8 hospitals between January 2002 and December 2011, was performed. Patients’ mean age was 53.6±10.74 years. Seventy percent patients were men. Acute abdominal pain was a common symptom that mostly developed within 48 hr after the ingestion of raw fish, and which lasted for 1–28 days. Sixty percent patients had ingested raw fish before the diagnosis of colonic anisakiasis and 40% patients were incidentally found to have colonic anisakiasis during the screening colonoscopies. Leukocytosis and eosinophilia were each found in 20% of the patients. In all patients who underwent colonoscopy, the worms were removed with biopsy forceps, except in 1 case, and a definite diagnosis of anisakiasis was made. In some cases of colonic anisakiasis, colonoscopy may be helpful in the diagnosis and treatment to avoid surgical intervention.

and Anisakis pegreffii, two sibling species from the complex Anisakis simplex s.l., major etiological agents of anisakiasis

Proteolytic activity was studied in two sibling species of Anisakis (Nematoda: Anisakidae), A. simplex s.s. and A. pegreffii, throughout their in vitro development from third larval stage (L3) from the host fish (L3-0h) to fourth larval stage (L4) obtained in culture. Proteases have a significant role in the lifecycle of the parasite and in the pathogen-host relationship. Proteolytic activity peaks were detected at pH 6.0 and 8.5. Protease activity was detected in all the developmental stages of the two species studied at both pH values. These pH values were used for assaying with specific inhibitors which permitted the determination of metalloprotease activity, and, to a lesser extent, that of serine and cysteine protease. Aspartic protease activity was only detected at pH 6.0. At this pH, L4 larvae showed higher proteolytic activity than L3 larvae in both species (p < 0.001), the majority of activity being due to metalloproteases and aspartic proteases, which could be related to nutrition, especially the latter, as occurs in invertebrates. At pH 8.5, proteolytic activity was higher in A. simplex s.s. than in A. pegreffii (p < 0.01). At this pH, the majority of activity was due to metalloproteases in all developmental phases of both species, although, in L3-0h, the activity of these proteases was significantly higher (p < 0.03) in A. simplex s.s. than in A. pegreffii. This could be related to the greater invasive capacity of the former. Serine proteases have frequently been implicated in the invasive capacity and pathogenicity of some parasites. This may be related to the significantly higher activity (p ≤ 0.05) of serine protease in all the larval stages of A. simplex studied at pH 6.0. Thus, there are interspecific differences in proteases that have been related to pathogenesis in nematodes. These differences could thus be contributing to the previously reported differences in pathogenicity between these two Anisakis species.

Anisakis Nematodes in Fish and Shellfish- from infection to allergies

Anisakidosis is a zoonotic parasitosis induced by members of the family Anisakidae. The anisakid genera includes Anisakis, Pseudoterranova, Hysterothylacium and Contracaecum. The final definitive hosts of these nematodes are marine mammals with a complex life cycle. These nematode parasites use different crustaceans and fish species as intermediate or paratenic hosts and humans are accidental hosts. Human anisakiasis, the infections caused by members of the genus Anisakis, occurs, when seafoods, particularly fish, contaminated with the infective stage (third stage larvae [L3]) of this parasite, are consumed. Pseudoterranovosis, on the other hand is induced by members of the genus Pseudoterranova. These two genera of anisakids have been implicated in human disease globally. There is a rise in reports of gastro-intestinal infections accompanied by allergic reactions caused by Anisakis simplex and Anisakis pegreffii. This review provides an update on current knowledge on Anisakis as a food-borne parasite with special focus on the increasingly reported diversity of fish and crustacean hosts, allergens and immunological cross-reactivity with invertebrate proteins rendering this parasite a significant public health issue.

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Anisakis, is a foodborne zoonotic parasite.

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Humans are accidental hosts of Anisakis L3 larva.

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Consumption of Anisakis parasite-contaminated seafood causes human anisakiasis.

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Zooplankton (Crustaceans: Krills, Squids, Crayfish) composition in fishing regions contribute to Anisakis parasitosis.

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Anisakis is the parasite with the largest number of registered allergens with the IUIS.

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.

Anisakiasis: The risks of seafood consumption

Context and Aims

Japanese cuisine is now popular worldwide, and consumption of raw fish has thus increased at sushi bars and Japanese restaurants outside Japan. Anisakiasis, also known as herring-worm disease, is caused by ingesting larval nematodes in raw seafood and is a common illness in Japan. However, due to the rising popularity of Japanese food, gastroenterologists outside Japan need to be familiar with this disease.

Subjects and Methods and Results

We treated 158 patients presenting with acute gastrointestinal manifestations caused by anisakiasis from April 1991 to April 2000. One or more nematodes were removed endoscopically within 48 h of presentation in 44% of these patients, which resulted in prompt resolution of symptoms. Major endoscopic findings were gastric ulcer accompanied by hemorrhage, erosion, redness, and edema of the gastric mucosa in areas penetrated by larvae and other areas.

Conclusions

Endoscopy was valuable for the diagnosis and treatment of anisakiasis. We recommend endoscopy in suspected cases of anisakiasis. Moreover, it is desirable to combine complementary tests such as immunological tests/IgE measurement. As the popularity of Japanese cuisine increases, reports of anisakiasis are likely to be more frequent in countries other than Japan.

[Anisakiasis Induced Segmental Jejunum Obstruction]

Human anisakiasis is a disease caused by an infestation of the third stage larvae of family anisakidae. The ingested larvae invade the gastrointestinal wall, causing clinical symptoms that include abdomen pain, nausea, and vomiting. Although enteric anisakiasis is extremely rare, it can induce intestinal obstruction. We report a case in which emergency surgery was needed due to intestinal obstruction that coincided with symptoms related to anisakiasis, along with a brief literature review.

A scanning electron microscopy study of Anisakis physeteris molecularly identified: from third stage larvae from fish to fourth stage larvae obtained in vitro

The development of the fourth larval stage (L4) of Anisakis physeteris was studied using scanning electron microscopy (SEM), comparing it with third larval stage (L3) recently obtained from the host fish, blue whiting (Micromesistius poutassou), from the western Mediterranean Sea (east coast of Spain, zone FAO 37.1.1). After molting to L4, samples of the parasite were examined at different times in order to observe their development. Following collection of the L4, a small portion was taken from the middle of the larva for molecular identification, confirming in all cases that it was A. physeteris. The anterior and posterior sections of the larvae were prepared for morphological study by SEM. The development of a row of denticles on each of the three prominent lips, almost reaching the buccal commisures, was observed in the L4. Pores of unknown function were found in the upper external part of each lip. Clearly developed cephalic papillae, amphids, and deirids were also observed in L4, while, although present in L3, these were beneath the cuticle. Phasmids were detected in L4 but not in L3. The L4 tail finished in a conical lobe with a blunt point, absent in L3. In the oldest L4, some preanal papillae were observed beneath the cuticle in males, while, in females, the vulva could be seen by light microscopy, apparently still covered by the cuticle.

Molecular Epidemiology of Anisakis and Anisakiasis: An Ecological and Evolutionary Road Map

This review addresses the biodiversity, biology, distribution, ecology, epidemiology, and consumer health significance of the so far known species of Anisakis, both in their natural hosts and in human accidental host populations, worldwide. These key aspects of the Anisakis species' biology are highlighted, since we consider them as main driving forces behind which most of the research in this field has been carried out over the past decade. From a public health perspective, the human disease caused by Anisakis species (anisakiasis) appears to be considerably underreported and underestimated in many countries or regions around the globe. Indeed, when considering the importance of marine fish species as part of the everyday diet in many coastal communities around the globe, there still exist significant knowledge gaps as to local epidemiological and ecological drivers of the transmission of Anisakis spp. to humans. We further identify some key knowledge gaps related to Anisakis species epidemiology in both natural and accidental hosts, to be filled in light of new 'omic' technologies yet to be fully developed. Moreover, we suggest that future Anisakis research takes a 'holistic' approach by integrating genetic, ecological, immunobiological, and environmental factors, thus allowing proper assessment of the epidemiology of Anisakis spp. in their natural hosts, in human populations, and in the marine ecosystem, in both space and time.

Anisakiasis Involving the Oral Mucosa

Anisakis is a parasite with life cycles involving fish and marine mammals. Human infection, anisakiasis, occurs with the ingestion of raw infected seafood and usually presents with acute or chronic gastrointestinal symptoms from esophageal or gastric invasion. We report a rare caseinvolving the oral cavity. A 39-year-old male presented with oral and sub-sternal pain of one day duration after eating raw cuttlefish. Physical examination revealed areas of erythema and edema with a central white foreign particle on the labial and buccal mucosa. With microscopic field we could remove the foreign material from the lesions. The foreign material was confirmed to be Anisakis. Anisakis was also removed from the esophagus by esophagogastroduodenoscopy. The patient was discharged the following day without complication. Anisakiasis is frequently reported in Korea and Japan, countries where raw seafood ingestion is popular. The symptoms of acute anisakiasis include pain, nausea, and vomiting and usually begin 2–12 hours after ingestion. The differential diagnosis includes food poisoning, acute gastritis, and acute pancreatitis. A history of raw seafood ingestion is important to the diagnosis of anisakiasis. Treatment is complete removal of the Anisakis to relieve acute symptoms and prevent chronic granulomatous inflammation.

Distinguishing gastric anisakiasis from non-anisakiasis using unenhanced computed tomography

PURPOSE

This study aimed to assess the diagnostic performance of unenhanced computed tomography (CT) for distinguishing gastric anisakiasis from non-anisakiasis gastric conditions and the reproducibility of CT findings.

METHODS

Fifty-six anisakiasis and 74 non-anisakiasis cases with gastric wall thickening on urgent observation using unenhanced CT were included. Using a κ analysis, two radiologists independently assessed the reproducibility of CT findings, including "circumferential gastric wall thickening," "gastric wall thickening extending more than two segments," "bulky and low-density gastric wall thickening," "increase in peri-gastric fat density," and "ascites." An anisakiasis diagnostic score (ADS) was developed for this study and was used to quantitatively evaluate the CT findings. An anisakiasis diagnostic prediction (ADP) with an appropriate cutoff value was used to further evaluate the ADS. Two radiologists reassessed the findings in consensus to determine the sensitivity, specificity, and accuracy of the CT findings, including the ADP and ADS area under the curve (AUC).

RESULTS

Considering reproducibility, a substantial agreement (0.6 < κ < 0.8) was achieved for all findings except "circumferential gastric wall thickening" (κ = 0.499), whereas for diagnostic performance, all findings except ascites were significantly more frequent among the anisakiasis cases. "Bulky and low-density gastric wall thickening" had the highest sensitivity (98%), whereas "gastric wall thickening extending more than two segments" had the highest specificity (80%). The ADP sensitivity, specificity, and accuracy were 91%, 84%, and 87%, respectively. The AUC was 0.902 (p < 0.05).

CONCLUSIONS

Unenhanced CT findings are useful for distinguishing anisakiasis from non-anisakiasis gastric conditions with sufficient reproducibility.

Human gastric hyperinfection by Anisakis simplex: A severe and unusual presentation and a brief review

Anisakiasis is an emerging marine food-borne zoonosis resulting from the accidental ingestion of Anisakis larvae, through the consumption of raw or undercooked infected seafood products. The first case of human gastric hyperinfection by Anisakis simplex with an unusual and severe presentation, occurring in a Portuguese woman, is described in this article. Over 140 anisakid larvae were removed by gastroscopy. Massive infection is uncommon in areas where the consumption of raw fish is not part of the traditional diet, as is the case in Portugal. The increased consumption of raw seafood products is considered a health determinant in the rise in cases of anisakiasis. However, clinicians should be aware of the emergence of these infections, not only because of the new dietary habits of the population, but also because of the high prevalence of Anisakis larvae in the different fish species usually consumed by the population, collected on the Portuguese coast.

Anisakidae nematodes isolated from the flathead grey mullet fish (Mugil cephalus) of Buenaventura, Colombia

Anisakiasis is a parasitic infection caused by larval stages of nematodes of the genus Anisakis, Pseudoterranova and Contracaecum, of the Anisakidae family. The lifecycle of these nematodes develops in aquatic organisms and their final hosts are marine mammals. However, humans can act as accidental hosts and become infected with infective stage larvae (L3) by consuming raw or undercooked fish or shellfish carrying the parasite. Of this group of parasites, the genus Anisakis is the most studied: its presence in humans is associated with non-specific gastrointestinal symptoms or allergic responses that can trigger anaphylactic shock. The lack of studies in anisakiasis and Anisakis in Colombia has resulted in this infection being little-known by medical practitioners and therefore potentially underreported. The objective of this study was to identify anisakid nematodes in the flathead grey mullet fish (Mugil cephalus), caught by artisanal fishing methods and commercialized in Buenaventura. Morphological identification was carried out by classical taxonomy complemented by microscopy study using the histochemical technique Hematoxylin-Eosin. Nematodes of the genus Anisakis were found in the host M. cephalus. The Prevalence of Anisakis larvae in flathead grey mullet fish was 33%. The findings confirm the presence of Anisakis sp. in fish for human consumption in the Colombian Pacific region, a justification for further investigation into a possible emerging disease in this country.

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The research confirmed the presence of anisakids in the fish M. cephalus in Colombia.

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First report such anisakids in fish from Colombia's Pacific coast.

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Is confirmed the presence of the genus Anisakis in the country.

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Anisakis spp. is associated with allergic reactions and gastro-allergies in humans.

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The presence the anisakids suggests a possible emerging zoonotic disease in Colombia.

Invasive anisakiasis by the parasite Anisakis pegreffii (Nematoda: Anisakidae): diagnosis by real-time PCR hydrolysis probe system and immunoblotting assay

Background

Anisakiasis is a fish-borne zoonosis caused by Anisakis spp. larvae. One challenging issue in the diagnosis of anisakiasis is the molecular detection of the etiological agent even at very low quantity, such as in gastric or intestinal biopsy and granulomas. Aims of this study were: 1) to identify three new cases of invasive anisakiasis, by a species-specific Real-time PCR probe assay; 2) to detect immune response of the patients against the pathogen.

Methods

Parasite DNA was extracted from parasites removed in the three patients. The identification of larvae removed at gastric and intestinal level from two patients was first obtained by sequence analysis of mtDNA cox2 and EF1 α-1 of nDNA genes. This was not possible in the third patient, because of the very low DNA quantity obtained from a single one histological section of a surgically removed granuloma. Real-time PCR species-specific hydrolysis probe system, based on mtDNA cox2 gene, was performed on parasites tissue of the three cases. IgE, IgG₄ and IgG immune response against antigens A. pegreffii by Immunoblotting assay was also studied.

Results

According to the mtDNA cox2 and the EF1 α − 1 nDNA sequence analysis, the larvae from stomach and intestine of two patients were assigned to A. pegreffii. The Real-time PCR primers/probe system, showed a fluorescent signal at 510 nm for A. pegreffii, in all the three cases.

In Immunoblotting assay, patient CC1 showed IgE, IgG₄ reactivity against Ani s 13-like and Ani s 7-like; patient CC2 revealed only IgG reactivity against Ani s 13-like and Ani s 7-like; while, the third patient showed IgE and IgG reactivity against Ani s 13-like, Ani s 7-like and Ani s 1-like.

Conclusion

The Real-time PCR assay, a more sensitive method than direct DNA sequencing for the accurate and rapid identification of etiological agent of human anisakiasis, was successfully assessed for the first time. The study also highlights the importance to use both molecular and immunological tools in the diagnosis of human anisakiasis, in order to increase our knowledge about the pathological findings and immune response related to the infection by zoonotic species of the genus Anisakis.

Anisakis (Nematoda: Ascaridoidea) from Indonesia

Despite Indonesia's high marine biodiversity, there is a lack of information regarding fish parasites in Indonesian waters. During a sampling of 136 teleost species from Indonesian waters, 22 of them were infected with larvae of Anisakis Dujardin, 1845, a genus with zoonotic potential. We genetically identified 118 worms, provide a revision of all available sequences of the ITS-1-5.8S-ITS-2 marker from Indonesian Anisakis in GenBank (n = 125), and establish 16 new host records. So far, 53 Indonesian teleosts harbour Anisakis spp., 32 of them with known sequence data, increasing the worldwide teleosts with genetically identified Anisakis from 155 to 177. Sequence analyses of this marker in the 243 Anisakis specimens identified 3 Anisakis sp. HC-2005 and 39 (16%) A. typica (sensu stricto). A. berlandi and A. pegreffii are reported for the first time from teleosts in the equatorial region and A. physeteris from the Pacific Ocean. The latter 3 species were exclusively found in the migratory scombrid Auxis rochei. Most common infection sites were the body cavity, with 299 (of 848) worms in the mesenteries surrounding the liver, and 129 unattached. Musculature infection was very low, demonstrating minor risk of anisakiasis for human consumers. A total of 193 worms (~79%) had a distinct genotype distinguished from A. typica by 4 positions in the ITS-1 region. This genotype is reported since 2008 as 'A. typica', 'sibling', 'Anisakis sp./type 1', 'sp. I', 'sp. 2' or 'sp. II'. To avoid further misleading identification, we hereby apply the subspecific entity Anisakis typica var. indonesiensis until description of the adults becomes available.

Proximal ileitis secondary to anisakiasis

Intestinal anisakiasis is a disease caused by human infection by Anisakis larva that can be found in undercooked fish that is increasing worldwide. The symptoms, typically abdominal pain, develop within 5-7 days after the fish intake. The diagnosis may be suspected based on common anamnesis (unfrozen fish intake) with abdominal pain or bowel obstruction and confirmed by blood serology. Resective surgery is only used in severe cases.

Anisakiasis: Report of 15 Gastric Cases Caused by Anisakis Type I Larvae and a Brief Review of Korean Anisakiasis Cases

The present study was performed to report 15 anisakiasis cases in Korea and to review the Korean cases reported in the literature. Total 32 Anisakis type I larvae were detected in the stomach of 15 patients by the endoscopy. Single worm was detected from 12 cases, and even 9 larvae were found from 2 cases. Epigastric pain was most commonly manifested in almost all cases, and hemoptysis and hematemesis were seen in 1 case each. Symptom manifestations began at 10-12 hr after eating fish in 73.3% cases. Endoscopy was performed 1-2 days after the symptom onset in most cases. The common conger, Conger myriaster, was the probable infection source in 7 cases. In the review of Korean anisakiasis cases, thus far, total 645 cases have been reported in 64 articles. Anisakis type I larva was the most frequently detected (81.3%). The favorable infection site of larvae was the stomach (82.4%). The common conger was the most probable source of human infections (38.6%). Among the total 404 cases which revealed the age and sex of patients, 185 (45.8%) were males, and the remaining 219 (54.2%) were female patients. The age prevalence was the highest in forties (34.7%). The seasonal prevalence was highest in winter (38.8%). By the present study, 15 cases of gastric anisakiasis are added as Korean cases, and some epidemiological characteristics of Korean anisakiasis were clarified.

Natural products: Perspectives in the pharmacological treatment of gastrointestinal anisakiasis

OBJECTIVE

To evaluate the activity of different natural products against L3 larvae of Anisakis type I.

METHODS

Information on investigations into the activity of natural products against the L3 larvae of Anisakis simplex was collected from scientific journals, books, theses and reports via a library and electronic search (using Pubmed, Scopus, Medline, Web of Science and ScienceDirect). The search terms included: natural products, medicinal plants, essential oils, terpenic derivatives, Anisakis, antinematodal activity.

RESULTS

In the literature reviewed numerous papers were found concerning the in vitro and in vivo activity against Anisakis type I of various natural products (plant extracts, essential oils and their major components). Analysis of the results showed that in vitro tests the Melaleuca alternifolia essential oil and the ar-turmerone isolated from Curcuma longa displayed the greatest activity. In vivo, the most active compound was perillaldehyde, the main component of Perilla frutescens essential oil.

CONCLUSIONS

This study shows that some natural products exhibited promising antianisakis properties.

Occurrence and prevalence of fish-borne Anisakis larvae in the spotted mackerel Scomber australasicus from Taiwanese waters

Anisakid nematodes have been found in a variety of marine fishes throughout the world and they are known to cause anisakiasis in human hosts. The present study investigated the prevalence of potentially zoonotic anisakid larvae in spotted mackerel caught from Taiwanese waters where fish represents an important food sources. Anisakis third-stage larvae (L3, n=502) were isolated from 250 spotted mackerel Scomber australasicus. Anisakis L3 larvae were divided morphologically into two types, Anisakis type I larvae had a longer ventriculus and mucron while type II larvae had a shorter ventriculus and no mucron. Anisakis species were identified by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of the internal transcribed spacer (ITS) regions of ribosomal DNA and direct sequencing. A simple molecular taxonomic key, utilizing RFLP by two restriction enzymes HinfI and HhaI, enabled the differentiation of the genus Anisakis. The prevalence, mean intensity and mean abundance of Anisakis nematodes recorded for the total specimens were 72.8%, 2.8 (1-15) and 2.0 (0-15), respectively. Anisakis pegreffii was determined to be the dominant species (prevalence=57.2%) and important agent of human anisakiasis. A recombinant genotype (Anisakis simplex sensu stricto × A. pegreffii) was identified as the subdominant species (25.3%) followed by Anisakis typica (10%), Anisakis physeteris (4.0%), Anisakis paggiae (3.0%) and Anisakis brevispiculata (0.5%). The topology of the maximum likelihood and neighbor-joining trees show two well supported clades: one includes the species of A. pegreffii and the other includes A. paggiae, A. physeteris and A. brevispiculata, while A. typica has basal position to all other Anisakis spp. analyzed. This study advances our knowledge of the prevalence of different Anisakis spp. in the spotted mackerel from Taiwanese waters, which is helpful for monitoring the fish populations throughout a diverse array of aquatic ecosystems. More importantly, we provide the concise characterization of multiple Anisakis spp. by PCR-RFLP, which could also be applicable for the rapid diagnosis of human anisakiasis.

Fishing area and fish size as risk factors of Anisakis infection in sardines (Sardina pilchardus) from Iberian waters, southwestern Europe

The sardine (Sardina pilchardus) is a fish commonly consumed and appreciated in many countries, although they are more likely to be eaten fresh in western Mediterranean countries such as Spain, Portugal, France or Italy. A molecular epidemiological survey of sardines from 5 fishing areas of the Spanish Mediterranean (Málaga, southern Spain) and Atlantic coasts (southern: Cádiz and Isla Cristina; northern: A Coruña and Ondarroa) was carried out to determine the presence of Anisakis spp. larvae. The highest prevalence of these larvae was observed in fish from A Coruña (28.3%), followed by Ondarroa (5%) and Cádiz (2.5%). No Anisakis larvae were found in fish from Málaga and Isla Cristina. Three Anisakis genotypes were identified: Anisakis simplex sensu stricto, Anisakis pegreffii and a hybrid genotype between these two species. A. pegreffii was the most prevalent species in A Coruña (71% of larvae). Only three Anisakis larvae (9% collected larvae) were located in the musculature of sardines: two were identified as A. pegreffii while the other was a hybrid genotype. Sardine infection was associated with fishing area and fish length/weight (length and weight were strongly correlated; Pearson's correlation 0.82; p<0.001). Risk factor multivariate analysis showed that the risk of infection increases 1.6 times for every additional cm in the length of the sardines from the same fishing area. Comparison of fish of equal length showed that in sardines from A Coruña the risk of parasitization is 11.5 times higher than in those from other fishing areas. Although the risk of infection by Anisakis through consumption of sardines is generally low due to the low epidemiological parameter values (prevalence 10%, mean intensity 1.7 (range 1-5) and mean abundance 0.17), as larger fish are more heavily parasitized, there is an increased risk of infection by Anisakis through consumption of large sardines which are raw or have undergone insufficient treatment (undercooked, smoked, marinated, salted, pickled, freezing,…).

Peppermint (Mentha piperita) and albendazole against anisakiasis in an animal model

OBJECTIVES

Therapy against anisakiasis requires invasive techniques to extract L3 , and an effective drug against this nematode is needed. The aim of this study was to determine the efficacy of peppermint essential oil (EO) and its main components against the parasite in comparison to albendazole, a drug currently prescribed to treat anisakiasis.

METHODS

We conducted in vitro experiments and studied an experimental model simulating the human infection in Wistar rats. We used polymerase chain reaction restriction fragment length polymorphism to identify A. simplex s.s. and A. pegreffii and determine any differences in their pathogenicity and susceptibility to the treatments.

RESULTS

The in vitro and in vivo experiments both showed that the larvicidal activity of peppermint EO, menthol, menthone and menthyl acetate is higher than that of albendazole. Large stomach lesions were observed in 46.7% of the albendazole-treated rats, whereas no gastrointestinal lesions were detected in those treated with peppermint EO, menthol, menthyl acetate or menthone.

CONCLUSIONS

In this animal model, treatment with peppermint EO or its main components was more effective than was treatment with albendazole. Lesions were more frequently produced by A. simplex s.s. larvae than by A. pegreffii larvae.

Food safety considerations in relation to Anisakis pegreffii in anchovies (Engraulis encrasicolus) and sardines (Sardina pilchardus) fished off the Ligurian Coast (Cinque Terre National Park, NW Mediterranean)

Engraulis encrasicolus and Sardina pilchardus are pelagic fishes of notable economic and gastronomic importance in the northwest Mediterranean (Ligurian Sea, Italy). The consumption of thermally unprocessed or lightly processed, marinated or salted anchovies and sardines presents a potential risk to acquire anisakiasis, a fish-borne parasitic disease in humans. Prevalence and abundance of Anisakis larvae in Engraulis encrasicolus and Sardina pilchardus from the Monterosso fishing grounds (Cinque Terre National Park, Ligurian Sea, Italy) were assessed, and the larvae were identified by morphological and PCR-RFLP methods. Anisakis larvae, all belonging to Anisakis pegreffii spp. were found in the visceral mass of 1050 anchovies (0.8% overall prevalence), whereas no Anisakis larvae were found in the 750 sardines examined. According to these data, the risk of acquiring anisakiasis from the consumption of raw or undercooked anchovies and sardines caught in the fishing area we investigated is very low.

An anisakis larva attached to early gastric cancer: report of a case

Gastrointestinal anisakidosis is a nematode infection caused by the ingestion of larvae-infected raw or undercooked fish. The Japanese like to eat raw or undercooked fish, so gastric anisakiasis is a common disease in Japan. However, reports of anisakiasis with gastrointestinal cancer are rare. A 63-year-old Japanese male was diagnosed with a small early gastric cancerous lesion associated with gastric anisakiasis. From our experience and based on a review of the literature, the attachment of an anisakis larva to early gastric cancer is not considered accidental.