Anizakidoz - Causes, Symptoms and Treatment .MF .

August 12, 2017 17:52 | Infectious Diseases

Anizakidoz - just recent problem in parasitology.Most clearly, the disease began to show itself to the middle of the XX century, when in 1955 the first case of human infection after eating salted herring was first registered in the Netherlands.

a long time, the disease was considered low hazard to humans since it has been found that up to the mature stage of the worm larvae do not develop in the human body.However, it soon became known that the larvae themselves are not only harmless, but also lead to serious health problems of the sick, and in the absence of aid, even serious consequences.

Anizakidoz - it parasitological human disease caused by the larvae of worms of Anisakidae family, is characterized mainly by the development of the pathological process in the gastrointestinal tract.

Geographical distribution anizakidoza

Along with the Netherlands, the bot with a certain frequency is recorded in many European countries (UK, France, Belgium, Sweden, Norway), North and South America, South-East

Asia (China, Korea, Japan and others).Quite rare, but the disease is found among the inhabitants of Russia - Central Region, Far East, Kamchatka and others.

In connection with the increase in consumption of the world's population salted seafood processing, and sometimes in the form of cheese and half-baked, to maintain a certain level of disease in almost any territory to which these products may be imported from various countries. number of references on the basis of the study of a large population of fish indicates a high invasiveness anisakids almost 100% of Pacific herring from the Japanese coast, 50% of hake in the same region, 25% cod and 35% pollock, up to 30% of mackerel and putasu and numberother species of fish.Such data should alert a person to respect the rules of the thermal treatment of the product and limit the use of raw or half-baked fish products.

Causes anizakidoza

Pathogen anizakidoza - larval stage of helminths belonging to Anisakidae family, genus Anisakis - Anisakis simplex (herring worm), the genus Pseudoterranova - Pseudoterranova decipiens, old Phocanema (cod worm), the genus Contracaecum, old Hysterothylacium and other, organized under the title "anisakids".This small nematodes, which body has a spindle shape with rounded ends, up to 65 mm for females and males at 55 mm.The head end of the worm has a lip in the amount of 3 pieces.The fertilized females produce eggs, which for the future development should be released into the environment and in the body of the intermediate host.Parasitological effects on human have just anisakids larvae.Larvae anisakids thermally moderately resistant - can withstand the temperature of + 45º, at a temperature of + 60º die within 10 minutes.By freezing to -18 ° killed larvae after only 14 days at -30º die within 10 minutes.

sources of infection. anisakids definitive hosts are marine mammals (such as cetaceans - whales, dolphins, and pinnipeds - seals, seals), several marine fishes - stingrays, sharks, and in some cases, fish-eating birds - herons, pelicans.It is in the gastrointestinal tract of the definitive host and parasitize mature females and males anisakids.

intermediate hosts are fish in freshwater and salt water, crayfish, mollusks.
There are additional hosts anisakids that may be carriers of the larvae - a series of marine fish - sea bass, cod, flounder, hake, sea trout, mackerel, capelin, and many others.

Herring - the source of infection anisakids

cycle anisakids development. After fertilization, the eggs into the environment, namely water.Here the eggs into larvae that fall to the intermediate hosts (molluscs, crustaceans, some fish), the body which can meet both simple larvae, and cysts (larvae, surrounded by a capsule).Invasiveness fish larvae reaches to 1000 per fish.Larvae reach a length of 3-4 cm, are pale yellowish appearance, sometimes with a brown tinge (depending on the type of agent).Cysts - rounded formation (larvae are placed therein in a spiral) with a translucent capsule around.Infected larvae are fish muscles, internal organs (liver and gall bladder, intestines), cavity masters body.The final hosts are infected by eating small fish, crustaceans and molluscs, invasive larvae anisakids.After catching fish larvae from the digestive system quickly penetrate into the inner and muscles, makes it possible for what is important early cutting of fresh fish (see. Prophylaxis).

mechanism of human infection - fecal-oral, but the way - the food. person infected by eating poorly thermally treated invasive marine fish, crustaceans, mollusks (ie, containing larvae in a viable state). at risk lovers ingestion of raw or insufficiently smoked, salted fish is not enough, the use of "five-minute" caviar and more.Certain practices in culinary preferences may contribute to contamination anisakids, for example, a weak-salted caviar, cooking "heh" of raw fish, a variety of national dishes, sushi, sashimi.

food that may be contaminated anisakids

anisakids Pathogenic action on the human body

After eating invasive larvae of fish and shellfish larvae penetrate the mucosa of the stomach, small and large intestines, and sometimes the throat.Mature individuals do not develop invasive duration lasts from several weeks to 3 months.

1) Due to the larvae there is a mechanical damage to the mucous membrane of the digestive system to produce inflammation, swelling of the mucous membrane, "eoznofilnyh granulomatosis infiltration" or granulomas.The granulomas are morphologically - larva, edema and inflammatory infiltrate with hemorrhages.

2) The development of intestinal obstruction due to the formed granulomas, as well as perforation of the intestinal wall with peritonitis.

3) sensitization of life anisakids products (similar to the action at toxocarosis) - an allergic reaction of the body, which is manifested in the form of urticaria, toxic and allergic edema, bronchospasm.

Clinical symptoms anizakidoza

The incubation period (interval from infection to onset of complaints) may be
to 1-2 weeks.The entire clinical picture is largely determined by the place of localization of larvae.The onset of the disease when finding them in the intestinal lumen of the symptoms can not be.

Gastric form anizakidoza (introduction of larvae in the stomach wall) is the most common
.Patients complain of pain in the epigastric region (stomach area), often acute, non-permanent, nausea and vomiting, and occasionally vomiting streaked with blood.Almost simultaneously in patients developing severe allergic reactions, hives, swelling of toxic-allergic and others.Often the symptoms are accompanied by the reaction temperature, the fever can be high - more than 38º.
The reverse (or retrograde) larvae drift from the stomach into the esophagus and throat, in which case patients are concerned cough, sore throat, and sometimes pain in the sternum.

Intestinal form anizakidoza is accompanied by abdominal pain in the umbilical region
, iliac areas, more on the right, and the pain can be sharp, intense, and therefore require the exclusion of "acute abdomen" surgeon.Pain accompanied by bloating, a feeling of increased churning in the stomach (rumbling), violation of the mushy stool to watery.Sometimes there are streaks of blood stool, mucus.

disease can occur acutely, subacute and chronic.The disease can be both mild and moderate to severe.In severe complications appear.

Complications anizakidoza

intestinal obstruction, perforation of the bowel wall with peritonitis, and in the absence of timely assistance and death.

Diagnostics anizakidoza

diagnosis is exposed on the basis of the data set:

1) epidemiological history - the fact of eating sea fish (herring, cod, etc.) and seafood (squid, crustaceans) inadequate heat-treated or raw or half-baked formstay on geographically endemic area for anizakidozu and consumption of seafood there.
2) Clinical data - symptoms associated with gastric or intestinal form of the disease in conjunction with an allergic reaction in the past or the present.Since nonspecific symptoms differential diagnosis will need to be carried out with a variety of diseases of the digestive system: gastritis, peptic ulcer and 12 duodenal ulcer, gastroenteritis, Crohn's disease, cancerous processes, pancreatitis, cholecystitis, appendicitis, diverticulitis, and other.
3) Laboratory tests:
- anisakids detection of larvae in the vomit and feces of patients - a rare detection method often no larvae or eggs of worms can not be detected by microscopy;
- Diagnostics: EGD (fibrogastroduodenoscopy) reveals swelling and mucosal erosion in the field of implementation of the larvae, and the larvae sometimes remove themselves;X-ray contrast.
- Surgery for resection of the stomach or of the intestines reveals infiltrated anisakids;
- The general analysis of blood can reveal leukocytosis, eosinophilia.
- Serological methods are of no practical use.

Anizakidoz - larvae in slizitoy shell at EGD

Treatment anizakidoza

Therapeutic measures at anizatsidoze reduced to:
1) of surgical interventions minimally invasive methods or conventional methods is possible in cases of suspected appendicitis, intestinal obstruction, intestinal perforationthat is, when complications arose.During the operation, often with the help of an endoscope is removed larvae, but should ensure their complete removal, as the remainder of the head end can lead to new granulomas.

Anizakidoz - removal of larvae

2) Drug therapy is conducted antiparasitic drugs (mebendazole, albendazole) short courses in which marked a positive therapeutic effect.

forecast severe disease complications in the event of the absence of timely and intensive care.

Clinical supervision is established after surgical intervention within one year of conducting EGD 1 time in 4-6 months.

Prevention anizakidoza

- Compliance with food culture (eating only proven thermally processed fish and seafood consumption avoiding raw or salted fish).
- Compliance with rules for processing suspicious sea fish and seafood.Rules include rapid evisceration of fish after catch to prevent the imminent introduction anisakids larvae in muscles of fish, frozen fish at -20º temperature for at least 120 hours (5 days), and at -18º - within 14 days;heat treatment of fish (at a temperature of + 80º or more is sufficient for death of larvae 20 minutes);sufficient prosol fish - 14% salt concentration for 10-12 days.
- Compliance with the rules of cutting fish (separate knife boards and utensils).
- helminthological examination of sea fish and seafood.

infectious disease doctor Bykov NI