Hymenolepiasis( dwarf tselement) - Causes, symptoms and treatment. MF.

We draw your attention to the topic of helminthiosis caused by a dwarf chain, which is more common in the children's age group from 4 to 14 years, with the possibility of forming microfocal diseases in preschool and school institutions, closed institutions, and family centers. This is due to the difficulty of complying with the sanitary and hygienic rules of conduct, the great contagiousness( infectiousness) and the features of immunity.

Hymenolepidosis is a parasitic disease of humans and small rodents caused by a dwarf chain of the genus Hymenolepis with a predominant digestive disorder.

The prevalence of hymenolepidosis on the planet is universal, however, the southern regions are leading in the incidence. High incidence of hymenolepiasis is registered in Afghanistan, Pakistan, Iran, Latin America, the African continent. In the former Soviet Union countries are Armenia, Georgia, Moldova, Azerbaijan, Ukraine, and in the Russian Federation - Tomsk Region, Amur Region, North Caucasus.

Causes of defeat with hymenolepidosis

The causative agent of the disease is dwarf tamarin( Hymenolepis nana) - a fine helminth of whitish color, about 3-5 cm long.

Dwarf chain

The chain consists of a head( scolex), neck, body( strobila).The head is spherical, has 4 suckers and a hem of hooks, which provides attachment to the inner wall of the intestine of the patient. Like all tapeworms, the body( strobila) consists of segments, the number of which reaches up to 300, the terminal segments being the largest and ripe, containing the eggs of the dwarf chain( oncosphere).Mature segments can contain up to 180-200 eggs of the chainworm.

Segment segments

Periodically the terminal segments are separated from the body, destroyed by enzymes in the intestinal cavity and, accordingly, the release of a huge number of eggs. Then the larvae of the chain are formed( cysticercoid or larvocysts).

Eggs are transparent, globular, up to 50 microns in diameter, inside the oncosphere with the embryo. On environmental objects, the eggs of the dwarf chain remain viable for 2 days, the fingers of the hands carry the infectious agent for 2-4 hours.

Egg eggs

Inactivation( neutralization) of eggs is possible at elevated temperature( up to +60 ° and above) for 15-20 minutes, at a low temperature( up to -4 ° - the temperature of the refrigerator) for 45 minutes. Also harmful to them are ultraviolet rays and the lack of moisture.

The cycle of development of the dwarf chain begins and ends in the human body.

Eggs get through the mouth with dirty fruits, vegetables, water into the small intestine, where from them come oncospheres, which are introduced into the villi of the intestinal mucosa, there develop to the cysticercoid or larva( it takes 5-7 days) - this is the tissue stagedevelopment of .

Then the larvae again exit into the lumen of the intestine and reattach to the mucosa, where they develop to the mature adult - this is the intestinal stage of development of the .

After 14 days, mature eggs appear in the terminal segments of the sexually mature specimen of the dwarf chain.

The whole cycle can last about 1-1.5 months. Sometimes the entire development cycle passes inside the host, without going outside, into the environment.

It should not be forgotten with hymenolepiasis about the possibility of autoinvasion( or a kind of superinvasia), when the villi of the intestine capture the liberated oncosphere of eggs and the development cycle continues without exiting the eggs outward. There is an autoinvasion with immunodeficiency in no more than 15% of the patients.

Hymenolepiasis, the development cycle of the dwarf chain

The source of infection ( the final and intermediate host) is a person whose intestines are parasitized by sexually mature dwarf species and eggs are discharged with feces into the environment. Also, the intermediate host of the dwarf chain can be rodents( hamsters, mice, rats).

The infection mechanism is fecal-oral. Infection occurs alimentary and contact way. Transmission factors for alimentary path are dirty vegetables, fruits, berries, water, and on the contact path - dirty hands, various household items( toys, dishes, towels, linens, door handles and others).Also, a certain role in the spread of infection is played by ordinary flies, on their paws the eggs of the chain can fall on both objects of the environment and products.

Susceptibility to hymenolepiasis is universal, however, children from 4 to 14 years are more often ill, and often foci are registered in preschool and school institutions, boarding homes, and in family centers. Urban residents are more often ill. Often dwarf tsepene occurs in the foci of enterobiasis.

Immunity after the transferred hymenolepiasis is unstable and unstressed, which means the possibility of repeated infection and autoinvasion( repeated self-infection).

Pathogenic action of dwarf chain on the human body.

- mechanical damage to the walls of the small intestine, necrosis of the villi of the intestinal mucosa( necrosis, ulcers at the attachment points, sometimes up to the muscle layer) due to the action of scolex hooks and parasitism of the chain;
- sensitizing effect( development of the body's allergic mood and toxic-allergic reactions) due to the products of vital activity and the disintegration of the parasite;
- intestinal microcirculation with the development of anemia;
- development of intestinal dysbiosis and avitaminosis C, B2, PP.

Symptoms of hymenolopidosis

Symptoms may be different, depending on the severity of the manifestations of helminthiosis. Patients present the following complaints in varying degrees of severity:

1) low-grade fever( body temperature increase to 37.5, less often 38 °);
2) dyspeptic syndrome( nausea, salivation, belching, heartburn, loose stools, anorexia, abdominal pain in most cases, flatulence, with severe pain in the abdomen, vomiting occurs);
3) astheno-neurotic syndrome( weakness, irritability, decreased efficiency, children lag behind in mental and physical development).
4) allergic manifestations( itchy skin with a rash, vasomotor rhinitis, manifestations of hives, possible development of asthmatic bronchitis or bronchial asthma).
5) a special appearance of patients: pallor of the skin, weight loss, dryness of mucous membranes and skin;
6) in the general blood test: low eosinophilia, moderate anemia, normo- and hypochromic( decrease of hemoglobin to 100 g / l and less), decrease in the number of leukocytes, increase in ESR.
In 30% of patients asymptomatic course of hymenolepiasis is observed.

Diagnosis of hymenolopidosis

Preliminary suspicion of hymenolepiasis is difficult and is based mainly on clinical data, as collecting epidemiological history is very difficult( most patients claim to wash their hands and food regularly).To help the doctor along with the main syndromes of hymenolepiasis "allergic mood" of the body( frequent allergic manifestations without objective reasons).

The final diagnosis is based only on laboratory confirmation, the main methods of which are as follows:

1) coproonoscopy( excrement is taken 3 times at 2-3 weeks intervals due to the peculiarities of the dwarf chain development cycle), the material must be fresh( morning feces).With a massive invasion of eggs, a lot is allocated, so a "native smear" method is sufficient. Eggs transparent, have a round-elliptical shape, opalescent.

Gimenolepidosis, coprocopy, egg chain

2) The method of enrichment( according to Füleleborn, Kalantaryan, Kato) is used for weak invasion, when eggs in feces are few. Sometimes, before the study, preparations are made for the use of phenasal( detectability is increased by 45-50%), however, this drug is prescribed only by the treating doctor.

Treatment of hymenolepiasis

In order to improve the quality of the therapy, as well as taking into account the peculiarities of the development of the dwarf chain, several simple treatment rules are necessary: ​​

1) The cyclicity of the ongoing therapy .Treatment involves exposure only to mature adults from the body of the patient, but does not at all affect the larvae( cysticercoids) of the chain. This feature obliges to conduct a repeated course of treatment in 5-7 days.

2) Preparatory stage before treatment. It is conducted to prevent side effects of antiparasitic drugs, reduce the risk of autoinvasion( repeated self-infection).A special easy-assimilating diet is prescribed( table 13 in Pevzdner), concomitant diseases are treated, intestinal adsorbents( lactofiltrum, filter, white coal, enterosgel and others) are prescribed, liver preparations( carpel, hepabenum, essliver, ovesol and others), drugs regulatingpatient's chair.

3) Recovery phase of after treatment. It is conducted to prevent side effects of antiparasitic drugs, reduce the risk of autoinvasion( repeated self-infection).They continue to take hepatoprotectors for the liver, prescribe probiotic drugs( bifiform, linpex, bion 3, biovestin, bifidum fote and many others), drugs that regulate the stool and exclude constipation - laxatives( frutolax, microlux, norma, dufalac and others).

4) Avoiding the development of toxic-allergic reactions to the antiparasitic agent may be the prescription of antihistamines ( zirtek, zodak, cetrine, claritin, tavegil, erius and others).

5) Actually antiparasitic therapy is conducted by fenasal. There are 2 courses for 4 days with 4-7-day intervals. The daily dose is divided into 4 divided doses and taken every 2 hours. For example, food - at 8, 13, 18 hours, and tablets - at 10, 12, 14, 16 hours. Another option - a daily dose of 1 reception on an empty stomach 1,5-2 hours before a meal for two days in a row. The drug is prescribed from 2 years of age in a dose of 1 to 2 grams, depending on the age.

Alternative scheme for fenasal reception - 2-day courses in the amount of 6 with a 4-5 day interval. The control of treatment is carried out not earlier than in 2 weeks after the spent therapy - investigate excrement.

Dispensary follow-up of for recurrent hymenolepiasis is established for up to 6 months. At this time, once a month, koproovoscopy is performed. Since recording, the patient is withdrawn in the case of 6 negative results of stool examination.

Prevention of hymenolepiasis

• Preventive measures in children's groups( hygienic education of children, hygiene skills - washing hands after toilet and before eating, nourishing a food culture - washing fruits and vegetables before meals).
• Regular wet treatment in rooms where there is a congestion of children and in potential homes, in other words, achieving a high sanitary level, fighting flies and other insects and rodents.
• Survey of newcomers to preschool and school groups, as well as entering the work in these institutions( coprocopy), a planned survey of these categories of persons twice a year.
• Timely detection of patients with hymenolepiasis and timely de-worming.

The doctor infektsionist Bykova N.I.