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Anisakis: symptoms and treatment

by Alivia Nyhan
Published: Last Updated on

The name anisakids may not sound like much to you, maybe more if we talk about the “bug that fish has.” The reality is that anisakis is a type of parasite of the nematode type (thin and elongated worm) 2 to 3 cm long, which fulfills part of its life cycle in fish and marine animals. This means that to become an adult requires living in a fish or marine animal and that, accidentally, it sometimes ends up infecting humans when they consume a fish or marine animal infected with this type of worm.

Have anisakids infected you? Do you want to know how it is treated and detected? Keep reading the following FastlyHealarticle on anisakid: symptoms and treatment.

Anisakis acquisition and life cycle

For the Anisakis to infect a human being, it requires completing a whole cycle:

  1. The eggs hatch in seawater.
  2. The larvae are found free in seawater.
  3. Crustaceans (lobsters, crabs, prawns, and barnacles) feed on these larvae.
  4. Fish (hake, Bonito, anchovy, anchovy, and sardine) or cephalopods (squid, octopus, cuttlefish) feed on these infected crustaceans.
  5. The worm lodges in the walls of the fish’s intestine, wrapped in a layer that protects it.
  6. The fish is ingested by marine mammals (dolphins, whales, killer whales, elephant seals, seals, sea lions, sea lions, or walrus).
  7. In the mammal, the worm mates and spawns, and the eggs are released into the sea in the feces of the marine mammal.

As you can see, humans are not included in the regular life cycle of Anisakis; however, if humans eat undercooked or raw meat from infected fish, they can contract the infection, just like a marine mammal.

The fish in which we can find A anisakids most frequently are:

  • Sardina
  • Cod
  • Boquerón
  • Herring
  • Salmon
  • Pout
  • Hake (almost 100% of Cantabrian hakes greater than 65 cm in length have Anisakis )
  • Whiting
  • Mackerel
  • Bonito (nearly 80% of large Bonito has Anisakis )
  • Mackerel
  • Rape
  • Anchovy

Anisakis causes an allergic reaction in fish, similar to poisoning, so these animals are sick when fished. Although we must never forget that to contract Anisakis, we must eat raw or undercooked fish, with which, taking care to cook it properly, we can eliminate the risk of contracting it.

Anisakis symptoms

A few hours after ingesting the parasite, the person will begin to notice the first symptoms of contagion, among which are:

  • Abdominal pain.
  • Sickness.
  • Vomiting

This is the initial response of the body to try to remove the parasite from our body, to try to eliminate it through vomiting. However, suppose that is not enough, and the parasite passes into the intestine. It can give a severe allergic-type reaction in the intestine, which can begin up to 15 days after ingesting the contaminated food. The symptoms can be very similar to those that appear with Crohn’s disease:

  • Abdominal pain.
  • Diarrhea.
  • Fecal incontinence
  • Rectal bleeding.
  • Weightloss.
  • Fatigue.

Although severe pain at the site where the parasite enters the intestine, or even obstructions, have also been described, which would require emergency abdominal surgery.

Another manifestation of Anisakis is the allergic type, which can be:

  • From mild hives (with itching and skin lesions).
  • Even the most severe allergic reaction, anaphylaxis, in which the whole body goes into a state of failure, can swell the throat, block the air, and be life-threatening.

How to know if you have anisakiasis

The diagnosis is made by suspicion; this means that the doctor will ask questions, and it is essential to highlight the intake of raw or undercooked fish, for example, sushi. Then tests will be carried out to identify Anisakis with certainty, and treatment can be started; among the more specific tests is endoscopy, which involves introducing a small cable with a camera at the end through the mouth to the first part of the intestine, where the larvae are visualized, or the histopathological examination can be performed under the microscope of a biopsy taken during endoscopy, or during abdominal surgery if there is obstruction.

Anisakis treatment

Anisakis treatment is merely symptomatic; gastric mucosa protectors such as omeprazole are given; although the idea is to remove the parasites by endoscopy, being vital to make the diagnosis early.

In the case of intestinal obstructions due to the allergic reaction that Anisakis causes in the intestine, corticosteroids can be administered to reduce inflammation and avoid having to resort to surgery. Surgical intervention may be necessary if the rash does not subside with the drug. To release the intestinal tract that is blocked.

In the case of allergic reactions, treatment with antihistamines and corticosteroids is given to reduce the manifestations. In the case of anaphylaxis, hospitalization is required to ensure that the airway does not close and administer corticosteroids and antihistamines in a more controlled manner.

Prevention of parasitization by Anisakis

Since 1993 standards have been established in the European Union to combat this parasite; according to some sources, Anisakis larvae survive in fish unless it is frozen at temperatures below -60ºC and then cooked.

In addition, visual inspections are carried out to detect highly parasitized fish and thus dispose of them and prevent them from reaching human consumption. Restaurants are also required to freeze all fish used for raw preparations, thus ensuring that there is no possibility of transmission of Anisakis to diners.

Some recommendations to prevent anisakis are:

  • know the risk of acquiring the parasite when consuming raw fish
  • avoid eating the belly of fish, especially those known to be infected,
  • cook over 60º for at least two minutes
  • freeze at -20ºC for at least three days

This article is merely informative, at FastlyHeal .com we do not have the power to prescribe medical treatments or make any diagnosis. We invite you to see a doctor in the case of presenting any condition or discomfort.

If you want to read more articles similar to Anisakis: symptoms and treatment , we recommend that you enter our Digestive System category .

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