[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.

Trends in Anisakis simplex Global Research: A Bibliometric Analysis Study.

Objective: Anisakis simplex is a fish-borne zoonotic parasite. Although this parasite has been known since the 19th century, publications on anisakiasis have increased in recent years. Despite this, this subject has yet to be well studied by bibliometric analysis. This study was conducted to show the research points and trends of A. simplex. Methods: The Web of Science Core Collection (WoSCC) was mined for articles on A. simplex. The VOSviewer software visually evaluated countries, institutions, authors, references, and keywords in this field. Results: A total of 1362 publications were included in this bibliometric analysis. The included publications were published between 1970 and 2022 from 79 countries, mainly from Spain (n=456, 33.48%). The most prolific year was 2020 (n=74). The research area that attracted the most publications was parasitology (n=452), while the most productive author in this area was Cuellar C (n=53). "Anisakis simplex", "Anisakis" and "anisakiasis" were the most used three keywords. Conclusion: The number of publications on anisakiasis has been increasing over time, suggesting that A. simplex is becoming an increasingly important disease worldwide. Research cooperation should be established between researchers from developed and developing countries to determine effective control strategies for anisakiasis.

Serum IgA contributes to the comprehension of Anisakis simplex associated chronic urticaria.

The phenotype of allergic diseases associated with Anisakis determines the pattern of cytokines related to antibody production. However, the role of serum IgA and the immunomodulatory mechanisms exerted by active infection of L3 or passive mucosal contact with A. simplex specific antigens has not been studied before. We measured serum cytokine by flow cytometry (IL-2, IL-4, IL-6, IL-10, TNF-α, IFN-γ, IL-17A, TGF-ß1) and antibody levels (IgE, IgG4, IgA) by ELISA against total and excretory-secretory (ES) antigens, Ani s 3,and the group of major allergens Ani s 1, Ani s 7, and Ani s 13 in sera from 10 patients with gastro-allergic anisakiasis (GAA), 11 Anisakis sensitization associated chronic urticaria (CU+) as well as 17 non-Anisakis-sensitized patients with chronic urticaria (CU-), compared with the urticaria control group (18 subjects). Specific IgE, IgG4 and IgA were high in the GAA, but IgA levels were significantly higher in the CU+ with respect the CONTROL group. We observed higher levels of the ratio IgA/IgG4 in CU+ than GAA group for Ani s 1, Ani s 7, Ani s 13 and ES. Furthermore, chronic urticaria (CU) patients showed significant lower levels of IL-10, IFN-γ and IL-17A than patients without CU. The anti-Ani s 13 IgA/IgG4 ratio correlated positively with pro-inflammatory cytokines and ratios (TNF-α, IL-17A, Th17/Th2, Type1/Type2 and TNF-α/IL-10) in CONTROL group. In general, Anti-Anisakis IgA/G4 ratio was high in CU patients. In conclusion, this study demonstrates the importance of serum IgA because it is associated with chronic urticaria independently of Anisakis sensitization.

Variation in the levels of anisakid infection in the European anchovy Engraulis encrasicolus (Linnaeus) from the Bay of Biscay during the period 2000-2023 (ICES Subarea 8).

The European anchovy Engraulis encrasicolus is one of the most important commercial species in the Bay of Biscay (ICES Subarea 8), and our analysis focused on the analysis of the temporal mean abundance, prevalence, and intensity of Anisakis spp. larvae species in anchovies from ICES Subarea 8 in the years 2000, 2001, 2014-2016, and 2019-2023. Prevalence in adult individuals of anchovy was only 1% in 2000 but increased to 90% in 2014. Since 2015, the prevalence has decreased, and the number of individuals affected in 2023 accounted for 17.6%. The mean abundance showed a similar trend, with a peak of 3.79 nematodes/anchovy in 2014, falling to 0.21 in 2023. The species A. simplex sensu stricto and A. pegreffii were identified by PCR/SANGER sequencing and PCR/RLFP techniques in 2019 and 2020. Anisakis simplex (s.s.) was the most abundant species and, according to the results returned by these two techniques, it accounted for an average of 62.4% and 52.1% of total nematodes in 2019 and 2020, respectively. The results of studies monitoring infection levels in anchovies showed that the mean abundance and prevalence changed over the course of the study period and that the proportion of different species of Anisakis is also subject to variation from year to year.

A novel rhabdovirus detected in Anisakis larvae distributed in the coastal areas of Japan: Viral genome analysis and possible coevolutionary relationship between virus and host nematodes.

In the last decade, it has become evident that various RNA viruses infect helminths including Order Ascaridida. However, there is still no information available for viruses infecting Anisakis. We herewith demonstrate the presence of a novel rhabdovirus from Anisakis larvae detected by next-generation sequencing analysis and following RT-PCR. We determined the nearly all nucleotide sequence (12,376 nucleotides) of the viral genome composed of seven open reading frames, and we designated the virus as Suzukana rhabdo-like virus (SkRV). BLASTx search indicated that SkRV is a novel virus belonging to the subfamily Betanemrhavirus, rhabdovirus infecting parasitic nematodes of the Order Ascaridida. SkRV sequence was detectable only in the total RNA but not in the genomic DNA of Anisakis, ruling out the possibility of SkRV being an endogenous viral element incorporated into the host genomic DNA. When we individually tested Anisakis larvae obtained from Scomber japonicus migrating in the coastal waters of Japan, not all but around 40% were SkRV-positive. In the phylogenetic trees of Betanemrhavirus and of the host Ascaridida nematodes, we observed that evolutional distances of viruses were, to some extent, parallel with that of host nematodes, suggesting that viral evolution could have been correlated with evolution of the host. Although biological significance of SkRV on Anisakis larvae is still remained unknown, it is interesting if SkRV were somehow related to the pathogenesis of anisakiasis, because it is important matter of public health in Japan and European countries consuming raw marine fishes.

A surgical case of inflammatory pseudotumor by hepatic anisakiasis.

Anisakiasis is a parasitic infection caused by the ingestion of raw or undercooked seafood infected with Anisakis larvae. It generally affects the gastrointestinal tract, particularly the stomach, but very rare cases have been reported in which infection of the liver leads to the formation of inflammatory pseudotumors. We herein report an extremely rare case of an inflammatory pseudotumor induced by hepatic anisakiasis that was laparoscopically resected for the purpose of both diagnosis and treatment. A 51-year-old woman underwent a routine medical checkup by ultrasound examination, which incidentally detected a 15-mm mass on the surface of S6 of the liver. Because a malignant tumor could not be ruled out on several preoperative imaging studies, laparoscopic partial resection of the liver was performed. Histopathological examination revealed Anisakis larva in the inflammatory pseudotumor, suggesting hepatic anisakiasis. This report describes an extremely rare case of an inflammatory pseudotumor induced by hepatic anisakiasis. Because the preoperative diagnosis could not be obtained by several imaging modalities, laparoscopic liver resection with a sufficient margin might be suitable for diagnosis and treatment of this disease.

[COMPONENT ANALYSIS OF THREE ANISAKIASIS ALLERGY CASES IN OUR DEPARTMENT].

Reactivity to an anisakis allergen component was examined in three patients with a history of an anisakiasis anaphylaxis. Case 1, a 38-year-old man, allergic symptoms appeared 0.5 hours after ingestion, and the component Ani s 1 and 3 were positive. Case 2, a 44-year-old woman, allergic symptoms appeared 4 hours after ingestion, and components Ani s 3 and 12 were positive. Case 3, a 36-year-old woman, developed allergic symptoms 7 hours after ingestion of fish and shellfish, and tested positive for Ani s 1, 4, and 12. Case 3 reacted strongly to both heated and unheated Anisakis extract, while cases 1 and 2 reacted weakly to heated Anisakis extract. The most common allergen was Ani s 12, followed by Ani s 1, when analyzed in conjunction with existing reports on 10 cases. Anisakis IgE was class 3 or higher in all cases. Analysis of 13 cases showed 2 cases sensitized to Ani s 4 and moderate or higher anaphylaxis, while Ani s 4-sensitized patients were reported to be more likely to develop severe disease. It is possible that the patients sensitized to Ani s 4 need to be careful about the severity of their allergic symptoms.

Zoonotic Marine Nematode Infection of Fish Products in Landlocked Country, Slovakia.

Fish products in Slovakia have been heavily infected with Anisakis spp. larvae, which causes human anisakiasis. We found larvae in all tested samples of frozen Atlantic herring. Anisakid allergen t-Ani s7 testing revealed 2 positive cases in humans, signaling need for health authorities to closely monitor zoonotic marine parasites, even in inland areas.

Anisakiasis in the Upper Esophagus: A Case Report.

Anisakiasis is caused by consuming raw fish contaminated with Anisakis sp. larvae and is extremely rare, especially when originating in the esophagus. We present a case of esophageal anisakiasis in a 61-year-old male who experienced severe precordial pain and radiating discomfort to the neck after consuming raw fish sashimi. Upper gastrointestinal endoscopy revealed the presence of a larva in the upper esophagus. On the basis of anatomo-morphological features, the worm was provisionally identified as Anisakis sp. and was easily extracted with forceps, which led to a prompt improvement in the patient's symptoms. This case highlights the importance of considering anisakiasis as a differential diagnosis in patients with gastrointestinal symptoms and a history of consuming raw fish.

Phylogenetic and phylogeographic analyses of Anisakis simplex sensu stricto (Nematoda: Anisakidae) from the common minke whale in Korean waters.

The genus Anisakis is among the most significant parasites to public health, as it causes anisakiasis, a parasitic infection in humans resulting from consuming raw or undercooked seafood. Although the infection status of i>Anisakis in second intermediate hosts, such as marine fishes and cephalopods, and humans have been severally reported in Korea, no information about the definitive host in Korean waters is available. In 2014, 2 adult gastric nematodes were collected from a common minke whale (Balaenoptera acutorostrata) found in the East Sea, Korea. These worms were identified as A. simplex sensu stricto (s.s.) by comparing the mitochondrial COX2 marker with previously deposited sequences. Phylogenetic and phylogeographic analyses of A. simplex (s.s.) worldwide revealed 2 distinct populations: the Pacific population and the European waters population. This is the first report on adult i>Anisakis and its definitive host species in Korea. Further studies on Anisakis infection in other cetacean species and marine mammals in Korean seas are warrantedi>Anisakis.

A case of hepatic anisakidosis caused by Anisakis pegreffii mimicking liver cancer.

Extra-gastrointestinal anisakidosis is rare. We herein report an Anisakis pegreffii infection in a patient with hepatic anisakidosis diagnosed based on its molecular identification. A 71-year-old male patient had a hepatic tumor presenting as a low-density area of 20 mm in diameter in segment 6 of the liver on abdominal ultrasonography, computed tomography, and magnetic resonance imaging. The surgically resected pathological specimen revealed a necrotizing eosinophilic granuloma containing nematode larvae, possibly an Anisakis larva. Molecular and phylogenetic analysis demonstrated Anisakis larvae belonging to A. pegreffii. The present results will help identify and characterize unknown Anisakis species in histological sections.

Intestinal anisakiasis: CT imaging findings-a 10-year descriptive study in a single center.

PURPOSE: The aim of this study was to retrospectively review cases of intestinal anisakiasis diagnosed by CT over a 10-year period and to evaluate imaging findings associated with the disease. METHODS: This retrospective study included 71 patients with clinical suspicion of intestinal anisakiasis in whom an abdominopelvic computed tomography (CT) was performed at a single institution between June 2011 and December 2021. To identify the cases, we used medical term search engines and the hospital's radiology case database. Clinical information was gathered from the medical records. A radiologist with five years of experience reviewed and analyzed the CT images to determine the characteristic findings of intestinal anisakiasis. RESULTS: The study included 47 confirmed cases of intestinal anisakiasis. The mean age of the patients was 52 years (range 18-87 years), being more frequent in men than women (26:21). All patients reported ingestion of raw fish, most commonly anchovies in vinegar (30/47, 63,8%). Abdominal pain was the predominant symptom, accompanied by nausea, vomiting, and occasionally fever. The most common clinical suspicions were intestinal obstruction (14/47, 29,8%) and appendicitis (10/47, 21,3%), whereas intestinal anisakiasis was suspected in only 2 cases prior to imaging. CT showed thickening of the bowel wall with submucosal edema in all patients, predominantly involving the ileum (43/47, 91,5%), usually in a relatively long segment (mean of 17,5 cm, range 10-30 cm). Simultaneous involvement of multiple bowel segments was observed in 16 cases (34%). Intestinal obstruction with dilatation of proximal loops (33/47, 70,2%), ascites (45/47, 95,7%), and mesenteric fat striation (32/47, 68,1%) were also common findings. CONCLUSION: This study demonstrates the value of computed tomography in suggesting the diagnosis of intestinal anisakiasis, which often presents with nonspecific clinical manifestations. The characteristic CT findings that provide diagnostic clues are bowel wall thickening with submucosal edema, typically involving a long segment of the ileum, with signs of intestinal obstruction, ascites, and mesenteric fat striation. Simultaneous involvement of several intestinal segments (typically the gastric antrum and right colon) is an additional finding to be considered and may provide a diagnostic clue.

Prevalence of Anisakis larvae in cultured mackerel Scomber japonicas in Japan and the relationship between the intensity of Anisakis infection in cultured mackerel and fish fatness.

Incidences of food poisoning caused by Anisakis have increased in Japan, and a significant number of anisakiasis cases in Tokyo attributed to the consumption of mackerel (Scomber japonicus) have been reported. There are two types of cultured mackerel in Japan: those cultured fully from controlled parent fish eggs and those cultured from wild juveniles collected from the sea. In this study, we aimed to investigate the prevalence of Anisakis larvae in cultured mackerel (184 fish) in 15 products and identified the species using molecular analysis to evaluate the risk of food poisoning. In total, 1567 Anisakis larvae were detected in 70 of 130 mackerel in 10 products; however, Anisakis larvae were not detected in 54 mackerel using artificially reared juveniles in 5 products. Moreover, 277 larvae were detected in fish muscle, and 98.6 % (273/277 larvae) were molecularly identified as Anisakis simplex sensu stricto (A. simplex). Conversely, 1043 Anisakis pegreffii larvae were identified genetically and/or morphologically but only 2 larvae were identified in the muscle. There was no significant relationship between the host coefficient of fatness and the infection intensity of Anisakis larvae in individual fish (Spearman's rank correlation coefficient test, P > 0.05). Based on the results of the analysis of the cytochrome c oxidase subunit2 (cox2) gene of A. simplex and A. pegreffii detected in this study, we attempted to estimate the catch area of the juveniles (Pacific stock and Tsushima Warm Current stock). The clusters on the phylogenetic tree of the cox2 gene of A. pegreffii from the mackerel presumed to be the two above mentioned geographic distributions were not separated and these geographic origins could not be estimated. This study revealed that mackerel cultured using wild juveniles are likely to be contaminated with Anisakis larvae, which can be detected not only in the visceral organs, but also in the muscle. Anisakis infection in cultured mackerel did not influence fish growth and evaluating the intensity of Anisakis based on the fatness level of the mackerel was complicated. To prevent anisakiasis caused by the consumption of mackerel cultured using wild juveniles, it is important to steadily control Anisakis through heating and freezing.

Clinical factors associated with acute abdominal symptoms induced by gastric anisakiasis: a multicenter retrospective cohort study.

BACKGROUND: Gastric anisakiasis typically causes severe abdominal symptoms; however, we incidentally detected asymptomatic gastric anisakiasis cases during esophagogastroduodenoscopy. The factors associated with developing acute abdominal symptoms induced by gastric anisakiasis remain unclear. Therefore, this study aimed to investigate the clinical factors associated with abdominal symptoms of gastric anisakiasis by comparing symptomatic and asymptomatic cases. METHODS: This was a retrospective cohort study involving 264 patients diagnosed with gastric anisakiasis at nine hospitals in Japan between October 2015 and October 2021. We analyzed patients' medical records and endoscopic images and compared the clinical factors between the symptomatic and asymptomatic groups. RESULTS: One hundred sixty-five patients (77.8%) were diagnosed with abdominal symptoms, whereas 47 (22.2%) were asymptomatic. Older age, male sex, diabetes mellitus, gastric mucosal atrophy, and gastric mucosal atrophy of the Anisakis penetrating area were significantly more common in the asymptomatic group than in the symptomatic group. Multivariate analysis revealed that age (p = 0.007), sex (p = 0.017), and presence or absence of mucosal atrophy (p = 0.033) were independent factors for the occurrence of acute abdominal symptoms. In addition, cases that were Helicobacter pylori naïve, with an elevation of white blood cells, or without an elevation of eosinophils were more common in the symptomatic group than in the asymptomatic group. CONCLUSIONS: Age, sex, and presence or absence of gastric mucosal atrophy were the clinical factors associated with the occurrence of acute abdominal symptoms. Older and male patients and those with gastric mucosal atrophy were less likely to show abdominal symptoms. The mechanisms of the occurrence of symptoms induced by gastric anisakiasis remain unclear; however, our results will help clarify this issue in the future.

Preliminary data on the occurrence of PAH and Anisakis spp. in Moroccan anchovies: Environmental parasitology and human health risk.

This survey focuses on an environmental parasitology study by investigating Polycyclic Aromatic Hydrocarbons (PAH) bioaccumulation and the occurrence of Anisakis spp. on common anchovies collected from Moroccan coasts over 9 months through chemical (PAH) and Biological (Biometrics and parasitic) analysis. Obtained results were statistically analyzed and human health risks from anchovies consumption were assessed. The results obtained highlighted the good biological and chemical status of this fish in all stations of Morocco's coasts. Anisakis spp. was present in only four stations in the Atlantic fringe (maximum prevalence 22.22 %). Results have shown non-significant differences for tissue nature (Muscle, viscera) or spatial variation and were within a low range of concentrations well below the European Commission standards. Results have shown no serious harmful risk for humans from this fish consumption (ILCR and HI), and statistical analysis had shown positive correlations between prevalence and Chr, prevalence and sex-ratio, and prevalence and weight.

Methods for inactivation of seafood Anisakis larvae and prevention of human anisakiasis: a mini-review.

Anisakiasis is an arising zoonosis induced by parasitic nematodes belonging to the family Anisakidae. Anisakiasis is often caused by the ingestion of larval nematodes in uncooked or minimally processed seafood dishes, which are regularly consumed by humans. Significant potential sources of infection are raw fish (e.g., sushi and sashimi) that can be found in traditional Japanese cuisine and can be part of the culinary tradition of consumption of raw or marinated fish that is particularly diffused in European countries. During the last five decades, the global prevalence of human anisakiasis has been rising, becoming an emergent major public health problem. Thus, there is an unmet need for well-defined and cost-effective methods aimed at killing Anisakis larvae, thus reducing the incidence of anisakiasis. In this mini-review, we discuss the clinical features of anisakiasis as well as the effectiveness and mechanisms of action of the main methods employed for increasing seafood safety and killing Anisakis larvae, including freezing, heating, use of high hydrostatic pressure, salting process, pepsin digestion method and use of garlic oil.

Worm globalization.

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

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.