Anisakidosis - Treatment And Diagnosis: Symptoms In Humans

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Anisakidosis - Treatment And Diagnosis: Symptoms In Humans
Anisakidosis - Treatment And Diagnosis: Symptoms In Humans

Video: Anisakidosis - Treatment And Diagnosis: Symptoms In Humans

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Video: Anisakiasis | Anisakis | Life cycle, symptoms, treatment | By phanindra gupta 2023, February
  • 1 What is anisacidosis?

    1.1 Causes of occurrence

  • 2 Symptoms of anisakidosis

    2.1 Anisakida development cycle

  • 3 Treatment of anisacidosis
  • 4 Prevention

When the parasite enters the human body, a worm disease develops. If we talk about anisakidosis, what it is, then it is a parasitic disease caused by the zoonotic helminth, which is a member of the Anisakidae family. The very first human case of anisacidosis was reported in the Netherlands in the middle of the 20th century. For a long time, doctors were confident that this parasite does not harm a person, until they realized that its larvae could significantly undermine the patient's health. In our article we will tell you everything about anisacidosis: symptoms and treatment of this ailment.

What is anisacidosis?

human anisakidosis
human anisakidosis

Human anisakidosis is provoked by the larvae of the parasite belonging to the genus Ascaridida. This helminth is spindle-shaped and outwardly similar to roundworms, but differs from them in larger sizes. It can grow up to 6.5 cm in length. The head end of the parasite is somewhat narrowed and has three pairs of suckers, with the help of which it attaches to the mucous membrane and organs of the host.

These worms are most often found in the muscles, viscera, and abdomen of fish, crustaceans and molluscs. The larvae can reach 0.3-0.7 cm in size. But there is a variety of these parasites that do not form cysts, but lay larvae, which can reach 60 mm in length. After eating infected fish and crustaceans, birds, marine mammals, and some species of predatory fish become infected. They are the ultimate hosts of the helminth.

Anisakid larvae are dangerous to human life, not only because they can cause intestinal obstruction, but also for the following reasons:

  • small larvae freely penetrate into other systems and organs of the human body and cause an inflammatory process and the formation of granulomas there;
  • any parasites in the human body provoke the occurrence of all kinds of allergic reactions (urticaria, bronchospasm, allergic edema).

Causes of occurrence

eating contaminated fish
eating contaminated fish

Anisakida infestations in humans occur when contaminated fish and insufficiently processed seafood are consumed. The main reasons for the development of this type of helminthiasis lie in insufficient heat treatment of fish, crustaceans and molluscs. So, all those who love fish (namely cold smoked), sushi, lightly salted herring, as well as people who eat seafood that have not undergone the necessary processing, are at great risk of infection. Even after catching the fish, the larvae can quickly penetrate the muscles and internal organs, so it is very important to butcher the fish immediately after catching.

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Children's preparations for enterobiasis

People are a dead-end developmental path for anisakids, since the parasite does not reach the state of sexually mature individuals in their body. Usually, this parasitic disease lasts no more than three months, but its consequences can persist and cause a problem to a person for many years. This is due to the toxic-allergic effect of the waste products of the helminth on the human body.

From the moment of infection until the first symptoms appear, it can take from a couple of hours to several weeks. The larva enters the submucosal or mucous layer of the intestinal tract. It is firmly fixed by means of the head end. In this place, edema and inflammation subsequently develop. Hemorrhage and ulceration sometimes appear. Subsequently, tissue necrosis and the development of eosinophilic tumor-like granulomas occur here.

Symptoms of anisacidosis

pain in the abdomen
pain in the abdomen

Signs of disease in humans may differ depending on where the parasite enters:

  1. If the larvae have settled in the stomach, then the patient will be disturbed by pain in the abdomen, constant nausea and occasionally vomiting. In this case, there may be an admixture of blood in the vomit. The temperature rises to significant numbers. Some patients have allergic manifestations.
  2. In the case of the introduction of larvae into the esophagus, the patient complains of abdominal discomfort and irritation in the throat. Often, against this background, a strong cough occurs.
  3. When the parasite is localized in the intestine, the patient is concerned about pain around the navel and in the iliac region on the right side. The disease is often manifested by flatulence and a strong rumbling in the abdomen. Often, the patient has all the symptoms that are characteristic of an acute abdomen.

If a person has anisakida, treatment depends a lot on the form of the disease. So, there is an acute, chronic and subacute form of anisakidosis. The mild form is characterized by the presence of only dyspeptic symptoms (loss of appetite, vomiting and nausea). In severe cases, pain is pronounced, there is bloating, constipation and even intestinal obstruction.

Anisakid development cycle

one fish contains a thousand larvae
one fish contains a thousand larvae

In its development, the parasite goes through several stages:

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What causes a person to have worms?

  1. Adults living in the body of marine mammals produce eggs, which enter the external environment with the faeces of these animals.
  2. From fertilized eggs in water bodies, larvae of the first stage are formed.
  3. They then develop to second stage larvae, which hatch from the egg and can swim freely.
  4. These individuals are eaten by small crustaceans and develop in their organisms into third stage larvae.
  5. After eating them, the parasites get to intermediate hosts (crustaceans, fish, molluscs). In their bodies you can find not only larvae, but also parasite cysts (these are embryos in capsules). One fish contains a thousand larvae. Here the parasite migrates into the abdominal cavity and grows up to three centimeters long.
  6. Further, when eating infected fish, crustaceans and molluscs, the final hosts of the parasite (marine mammals) are infected. In their body, the larvae develop to sexually mature individuals, reproduce and produce eggs. The cycle is closed.

Treatment of anisakidosis

Diagnosis of the disease is carried out on the basis of anamnesis and clinical data. It is important to check with the patient if they have eaten poorly processed seafood and fish. The presence of an allergic reaction is also taken into account. Differential diagnosis is very important to distinguish anisacidosis from ulcers. It makes no sense to do fecal analyzes and serological blood tests, since it will not be possible to identify characteristic changes and worms. Sometimes the larvae are found in the vomit. Also, for diagnostic purposes, you can perform EGD and contrast radiography. In the KLA, slight leukocytosis and eosinophilia are found.

treatment of anisakidosis
treatment of anisakidosis

There is no specific treatment for anisacidosis. Even if you have not treated this disease, it can go away on its own after three months. However, in this case, there is a high risk of the consequences of the toxic-allergic effects of the parasite.

If we talk about how to get rid of the disease, then anthelmintic drugs with a wide spectrum of activity are used for this. Usually, treatment is carried out with one of the following medications:

  1. Mebendazole. The action of this drug is aimed at suppressing the protein synthesis of the parasite. The drug practically does not have a systemic effect on the body, but it can accumulate in the larvae, causing their death.
  2. Thiabendazole belongs to low-toxic drugs, the mechanism of action of which is not fully understood. This drug is known to be especially effective in the treatment of hookworm infections.
  3. Albendazole is considered an equally effective drug. This drug is often prescribed for the treatment of infestations caused by pork tapeworm larvae.

If the disease gave dangerous complications, then surgery is indicated. This applies to cases of intestinal obstruction when an urgent bowel resection is required. The operation is usually done endoscopically. In this case, in the process of resection, you can remove the larvae. It is important to completely remove the parasite, as an unremoved head end will lead to the formation of new granulomas.

No less dangerous complication of the disease, which also requires urgent surgery, is intestinal perforation and peritonitis provoked by it. After surgical treatment, the patient should be under dispensary supervision throughout the year. Every six months or a quarter, an FGDS is required.


As for the prevention of this ailment, it is important to adhere to the following rules:

  • You should not eat raw or lightly salted fish, as well as seafood that has not been properly processed. The death of the larvae of the parasite occurs at 80 degrees, provided that such a temperature effect lasts at least 20 minutes.
  • Freshly caught fish must be gutted as early as possible so that the larvae do not have the opportunity to penetrate the muscles and organs.
  • You need to freeze fish for at least five days at a temperature of at least -20 degrees.
  • Salted fish is considered safe only if the salt concentration is at least 14 percent, and the salting process lasts at least 12 days.

Also, for preventive purposes, it is important to follow the rules for cutting raw fish. To do this, the kitchen must have a special knife and a separate cutting board. The catch that goes for sale is necessarily subjected to helminthological testing.


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