Anisakiasis B81.0

Author: Prof. Dr. med. Peter Altmeyer

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Last updated on: 29.10.2020

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Anisakidosis; Herring worm disease

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Parasitosis caused by the consumption of larvae of fish nematodes of the genus Anisakis and related roundworm genera (Pseudoterranova descipiens and others), with massive upper abdominal pain, nausea and vomiting. More rare are extraintestinal localisations such as acute (and chronic) urticaria and angioedema.

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Anisakis simplex is a worldwide fish parasite (herring worm) belonging to the nematode family, which mainly infests marine mammals. Man is a false host. Accidental ingestion by raw or little cooked fish. There are three known types of nematodes in fish. The species Anisakis simplex gave the disease its name. The nematode can be found in raw fish such as sushi or herring. The prevalence in herring is around 70%.

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Anisakiasis is very rarely observed in Germany (data from the Robert Koch Institute). Only a few hundred cases a year are known. Here, mainly countries are affected where raw fish is consumed. This is mainly Japan.

However, when the symptoms appear, the consumption of raw fish should be asked. Especially if no other cause can be identified. A specific serodiagnosis can be performed in various countries. Specific serodiagnosis can be carried out in various special laboratories.

Clinical features
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In the foreground is the gastrointestinal symptomatology. About 6-12 hours after ingestion of the larvae by eating raw fish, gastroenteritis with severe abdominal pain usually occurs. Occurrence of eosinophilic granulomas in the gastrointestinal tract. More rare are extraintestinal manifestations such as acute (and chronic) urticaria and angioedema. Small bowel obstruction, ileitis and appendicitis are rarer.

The symptoms are caused by the larvae of the nematodes, which penetrate the mucous membranes of the stomach and intestines. They cause pain and inflammatory local reactions. In the further course of the disease, nodular eosinophilic granulomas are formed due to local inflammatory processes. These can cause severe disorders up to an ileus or intestinal perforation. Since humans are a false host, the nematode larvae die after 2-3 weeks. However, the symptoms may persist.

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Gastroscopy, detection of nematodes in the stool.

Differential diagnosis
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Anisakiasis must be distinguished from the equally rare anisakis simplex allergy. The allergic symptoms can affect the skin, respiratory tract, gastrointestinal tract or circulation (up to anaphylactic shock).

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There is no effective antiparasitic therapy. There are indications for a therapy with the anthelmintics albendazole or tiabendazole. Symptomatic granulomas in the abdomen must be removed surgically if necessary. However, the disease often heals on its own.

Because of the limited therapeutic options, prophylaxis is of particular importance. Here it is important to know: The larvae die at temperatures above 60 °C or below -20 °C. They also do not survive brine. Therefore, crabs or sea fish (herring, mackerel) should only be eaten after sufficient previous heating or safe preservation (marinating, smoking). Deep freezing before further processing is also an effective preventive measure.

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The infection can be avoided by shock freezing the raw fish for a while or by soaking it in brine. Herring today must be deep-frozen before further processing.

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There is no obligation to report.

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  1. Ashida H et al (2017) Distinguishing gastric anisakiasis from non-anisakiasis using unenhanced computed tomography. Abdominal radiol (NY) 42:2792-2798.
  2. Caballero ML et al (2002) Specific IgE determination to Ani s 1, a major allergen from Anisakis simplex, is a useful tool for diagnosis. Ann Allergy Asthma Immunol 89:74-77.
  3. González-Fernández J et al. (2015) Haemoglobin, a new major allergen of Anisakis simplex. Int J Parasitol 45:399-407.
  4. Kobayashi Y et al (2015) Molecular Cloning and Expression of a New Major Allergen, Ani s 14, from Anisakis simplex. Shokuhin Eiseigaku Zasshi 56:194-9.
  5. Ramos L et al (2006) Anisakis Simplex-Induced Small Bowel Obstruction After Fish Ingestion: Preliminary Evidence for Response to Parenteral Corticosteroids. Clin Gastroenterol Hepatol 19: 667-671

  6. Shimamura Y et al. (2016) Common symptom of Uncommon Infection: Gastrointestinal Anisakiasis. Can J Gastroenterol Hepatol 5176502.
  7. Wedi B, Kapp A (2006) Current position of the role of allergic and non-allergic food hypersensitivity in urticaria. dermatologist 57: 101-107


Please ask your physician for a reliable diagnosis. This website is only meant as a reference.


Last updated on: 29.10.2020