Trichinosis - Causes, Symptoms and Treatment .MF .

August 12, 2017 17:52 | Infectious Diseases

Trichinosis - one of the most serious human parasitological disease with the presence of natural foci and only part of the registration in many countries, as well as in Russia.Acute development of the disease and the possible serious consequences of trichinosis are extremely relevant in the context of Parasitology.

Trichinosis - bot is a natural focal proliferation caused by nematodes of the genus of Trichinella, acute course characterized by the presence of specific "Nibble signs" that can lead to disability and even death.

Outbreaks of trichinosis correspond to the spread of natural reservoirs (bears, wild boars, badgers and others) and recorded in the USA, Germany, Poland, Ukraine, Belarus, the Baltic countries.In Russia, the greatest activity is registered in the Khabarovsk, Krasnoyarsk, Magadan Region, the Krasnodar Territory.There are also synanthropic (urban) centers of trichinosis, KDE reservoir can be pets - dogs, cats, pigs, and rodents.

Trichinosis, the scheme epidemic spread

Pathogen trichinellosis

Trichinella spiralis (female Trichinella 1.5-1.8 mm and fertilized - up to 4.4 mm, male of about 2 mm).In nature, there are 4 types of Trichinella: T. spiralis, T. nativa, T. nelson, T. pseudospiralis.This small, thread-like worms even have a round body and tapering ends.


able to form a capsule around itself having good protective function.Encapsulated larvae and resistant to high temperatures and freezing.Maintain boiling about 3 hours.Encapsulated larvae killed by the heat treatment of not less than 80º meat for about 4 hours.Smoked and salted meat encapsulated larvae have no effect.

Trichinosis, encapsulated larvae

development cycle Trichinella quite peculiar.One and the same body is to Trichinella, and basic and intermediate host.Ingested with the meat of animals infected with Trichinella muscle (it's larval stage).The larvae are released from the capsule and 1-1.5 days reach the stage of intestinal Trichinella (directly on the mucous membrane of the intestinal wall).

During the period of parasitism in the human intestine (about 42 - 56 days), one female lays about 1,500 larvae.After the intestinal mucosa they get into the lymphatic system and then into the bloodstream and spread throughout the body.After 5-8 days after the invasion (infection) larvae fall into the skeletal striated muscles (almost all organs, except the heart) - often the language of the forearm, the diaphragm, intercostal, deltoid, calf muscles.Then they release hyaluronidase, penetrate the sarcolemma of muscle fibers, which are encapsulated (capsules function - nourishing, protective).

6 months begins calcification of the capsule, which lasts about 2 years.At this stage of development of the helminth ends.The capsules larvae remain viable for 25 years or more.

Immunity trichinosis after suffering life but non-sterile (blood has antibodies that protect against reinfection, but in tissues encapsulated larvae are stored).

causes of trichinosis

The reservoir of infection and the source of parasitosis to humans in natural foci are wild animals - wild boars, badgers, bears, brown and white, fox, nutria, marine mammals -. Whales, seals, etc., and in the settlements pets- pigs, dogs.

Trichinosis, infection sources

mechanism infection - nutritional and path - food.Man is infected by eating insufficiently cooked contaminated meat.transmission factors can be pork sausage, bacon homemade, bacon, ham, bacon, bacon, and more.

Susceptibility to trichinosis is high enough.Enough about 10 grams of contaminated meat to start the invasion.Often ill in groups or families after a feast, hunting meal.
season for trichinosis most autumn-winter (when harnessing natural focus, hunting period), in the urban centers of - autumn (slaughter pigs).

Brief description of the development of human trichinosis

in the development of parasitosis distinguish two phases.

1) phase allergic reactions (lasts 2-3 weeks after infection) - sensitization occurs
(allergic alteration) waste products of the body and the death of worms.Develop expressed allergic reactions with damage of blood vessels and coagulation disorders due to the introduction of Trichinella larvae in muscles (allergic myositis occurs in the muscles).
The muscles around the larva forms a protective granulating shaft - formed capsule that prevents the flow of helminth antigens in the human body.Under the effect of immunosuppressive drugs (e.g., hormones) as well as an overactive immune system (for massive invasion), this process can be broken.There allergic myositis and mass mortality of larvae in the muscles, as well as in organs - formed nodular infiltrates of lymphoid cells, plasma cells, eosinophils.
2) Phase organ lesions (3-4 weeks after the invasion), which is associated with larvae entering the
bodies and develop their systemic vasculitis.

Trichinella in the muscle tissue

Clinical forms and symptoms of trichinosis

The incubation period (time from infection to onset of symptoms) is 10 - 25 days, but can be shortened to one week (with massive invasions) and lengthenup to 45 days (in mild forms).

Trichinosis can be acute or chronic.

By severity acute trichinosis divided into heavy, moderate and light form.There may be atypical (unusual with the clinic and symptoms) form trichinosis, which are worn out and asymptomatic.

acute trichinosis

The course of the disease are distinguished:
- acute phase, including phase allergic reactions and phase of organ lesions,
- period of convalescence (recovery).

Picture trichinosis is characterized by peculiar features of tetralogy:
1) fever,
2) edema syndrome
3) muscle aches,
4) high blood eosinophilia.

Onset acute, from the first day of illness there is a high fever.
1) Fever often relapsing-remitting or the wrong type.A few days
temperature rises to 40º, held at the same level for several days, then declines as politically.Some patients have low-grade fever (temperature up to 37º), which may persist for several months.In milder forms, the temperature may not rise.Fever is a manifestation of general intoxication (weakness, chills, headache, nausea).

2) One of the persistent symptoms of trichinosis are edema of the eyelids and face combined with conjunctivitis (because this feature is called trichinosis "odutlovatki").Appearing 1-5 days of illness can be stored for 1-2 weeks.In severe forms of edema develop more slowly and last longer.First, there are edema of the eyelids, brow, then the entire face.In severe cases the swelling goes down to the neck, trunk, upper and lower limbs - is a poor prognostic sign.

Swelling at trichinosis

3) 3 or more days of illness, most patients appear muscle pain different muscle groups.
first hurt leg muscles (usually calf), then the muscles of the buttocks, back, abdomen, arms, shoulders, neck, tongue, throat, eye movement, chewing.Muscle pain is often intnsivnye, when movements are amplified, palpation of the painful muscles.In severe cases there are severe myalgia with contractures, sometimes resulting in the patient immobilization.Muscle pain and swelling persist 1-3 weeks and may recur periodically, accompanied by fever (milder recurrences of the primary disease).

for the acute period of trichinosis is also characterized by:
- abdominal syndrome (abdominal pain, dyspepsia),
- allergic reactions in the form of polymorphic rash on the skin of the whole body (urticaria, roseolous, speckled).

4) characteristic for the acute period eosinophilia reaches a high level (80%), appears with the first days of illness
large as possible at 2-4 week (in mild - no more than 30%, with moderate - to 60%and more, with a heavy - the number of eosinophils is not much, but a sharp increase to 95% is a poor prognostic sign).

In severe organ lesions appear, emerging 3-4 weeks after infection.Organ lesions are often the cause of death.
1) myocarditis allergic nature - the main cause of death (tachycardia, hypotension, acute circulatory failure symptoms, collapse).The ECG - signs of diffuse myocardial damage.
2) lung (pneumonia with involvement in the pathological process of the pleura), which are associated with systemic vasculitis.
3) central nervous system (meningoencephalitis, encephalomyelitis).
4) liver damage.
5) trombogemorragichesky syndrome (impaired clotting).

total duration of illness by an average of 1-2 weeks (mild forms) up to 5-6 weeks.With timely treatment is started, these periods are shortened to 3-5 days.In severe trichinosis recovery period may take up to 6 months or more.The protracted convalescence in the form of asthenia (weakness, fatigue, decreased appetite), myalgia may occur in patients receiving immunosuppressive (immunosuppressive drugs, such as hormones) drugs.

In the absence of treatment may develop damage vital organs, and possible death.Mortality in trichinosis can reach 5%.However, not all forms of light can be correctly diagnose and prescribe treatment in time.It is likely that in mild trichinosis death does not happen, because in immunocompetent organism recovery can happen (but in a small percentage of cases).

diagnosis of trichinosis

preliminary diagnosis is based on clinical and epidemiological data.When collecting epidemiological history draws attention to the fact consumption of insufficiently cooked pork and meat of wild animals - wild boar, brown bear, deer;in the analysis of complaints pay attention to the characteristic "nibble" of clinical symptoms.

final diagnosis is based on laboratory studies:
1) detection of Trichinella larvae in the remnants of eating meat;
2) the detection of larvae in muscle biopsies (trichinelloscope) - take a calf or delnovidnuyu muscle;
3) serological diagnosis (Phragmites becomes positive with 15 days of illness, ELISA method);
4) dermatological and allergy tests (positive, with 2 weeks of illness, many years) are stored.

differential diagnosis spend with opisthorchiasis, strongyloidiasis, typhoid fever, erysipelas person pseudotuberculosis, yersiniosis.


Treatment Treatment includes specific (etiotropic) and pathogenetic therapy.

Tasks causal treatment: destroy intestinal Trichinella, to stop the production of larvae, to break the encapsulation process and increase the destruction of muscle Trichinella.

Apply: mebendazole (Vermoxum) - various schemes an average of 14 days of the course;mintezol (thiabendazole) - is less efficient than Vermoxum due to side reactions, but also used in some cases;Albendazole.

most effective for specific (causal) treatment in the incubation period, when it is possible to prevent clinical manifestations, or in the first days of the disease, when there are intestinal Trichinella.During muscle encapsulation step and reduces its effectiveness and can exacerbate the disease.

Specific treatment is necessary to "cover" the appointment of antihistamines (Claritin, zodak, zirtek, tsetrin, erius and others).

Purpose hormonal treatment indicated for severe forms of trichinosis and the development of complications (due to the influence on the process kapsuloobrazovaniya around larvae) - prednisolone administered in medium and high doses and short courses - from 40-80 mg / day for 5-7 daysfollowed by dose reduction and abolition of the drug in 1-1.5 weeks.Since hormones may lengthen the period and the amount of production of larvae in the intestine, it is recommended anthelmintic drugs used during the entire period of their application and a few days after their cancellation.

monitoring the effectiveness of treatment is carried out in 6-12 months (deworming efficiency - 90%).

pathogenetic therapy includes antipyretics, analgesics, non-steroidal anti-inflammatory drugs.

Prevention of trichinosis

Look for meat that you are cooking.Any foreign matter - a reason not to use it for food.If the infestation is massive, we can see yellow peas very fine fibers in the striated muscle, but with non-intensive invasion of sight.That is why the meat, which is sold in shops and markets, must necessarily pass-universal trichinelloscope.

Contaminated meat is not simply thrown away, it can eat stray animals and the disease will continue to spread.Such meat is treated with kerosene and buried in the ground to a depth of at least 1 meter.

And even normal in your opinion the meat must be subjected to prolonged heat treatment.

meat of wild animals should also be subject to trichinelloscope that established the current veterinary legislation, and if it finds at least one larvae - utilized.When there is no possibility to conduct trichinelloscope, cooking the meat should be continued for at least 6 hours.

infectious disease doctor Bykov NI