Helminths

To preserve the species, all parasites in the process of reproduction leave the host organism, passing into the external environment or the organism of a new host. The range of possible hosts and the mechanism of transmission of the parasite from one host to another (or from the host to the external environment and beyond) determine the pathways of parasite circulation and the diseases caused by animals and humans.

An important role in understanding the paths is played by the concept of carrier :

• mechanical - for example, arthropods , in the body of which the parasite does not go through the development cycle, but only moves considerable distances (for example, on the legs of a housefly);
• specific ( intermediate host ) - in the body of which the parasite develops on one of the cycles, for example, for echinococcus a person is an intermediate host, and the wolf is the final one.

By transmission method:

• contact (the pathogen penetrates intact skin and mucous membranes, for example, hookworms );
• food (swallowing eggs or larvae, for example with water);
  • Ascaris is isolated separately, since fresh eggs of this parasite are not invasive (they mature in the soil for about a month, but they can be stored in the soil for up to 3 years, transferring negative temperatures and ultraviolet light).

In the human intestines, the female roundworm lays up to 240,000 eggs daily. They are covered with three shells (the outer one is painted with bilirubin in the color of feces), they are very resistant to external influences. In the soil, at a certain temperature, humidity and oxygen supply, a larva develops in the egg. Its formation in the egg lasts from 2 weeks to several months (depending on the ambient temperature). When a mature egg enters the intestines of a person under the influence of digestive juices, the larva is released from the membrane and is introduced into the blood vessels of the intestinal walls. With blood flow, the larva begins a “journey” through the circulatory system to various organs of the body, but is activated only in the capillaries of the pulmonary alveoli (the larva is aerobic, but adult forms are anaerobic). The larva, feeding on blood, grows (up to 3-4 mm) and rises in the bronchi, causing a cough (4-5 days after the initial invasion). Through coughing and swallowing, the larva with mucus again enters the intestine, where it develops into an adult. Adult roundworm lives in the intestines for up to a year, continuously laying eggs leaving the feces. Helminth-related diseases are called helminthiases .

Representatives of roundworms (nematodes)

It is 20–40 cm long, the male is slightly smaller than the female and differs from her in the hooked back end of the body. Adult forms inhabit the small intestine, can actively crawl, their life expectancy is about a year; larval forms affect the respiratory system. Ascaridosis is a disease characterized by intoxication, often acute bowel obstruction, sometimes requiring emergency surgical intervention.

Another representative of nematodes is whipworm . It is about 2-5 cm long. A feature of the disease of trichocephalosis is that with its anterior hair-like end, it violates the integrity of the intestinal wall, feeding mainly on the host’s blood. Since the worm colonizes the large intestine, a secondary infection joins at the site of damage, which may cause the development of appendicitis . Intoxication and anemia are also noted as characteristic symptoms of this disease.

Most often - hermaphrodites , but there are dioecious (nematodes).

The development of helminths occurs in several stages, as a result of which they change several hosts ( biohelminths ) or develop without a change of owners ( geohelminths ). Usually, immature eggs are secreted into the external environment, where they ripen, enter the intermediate host, form a larva that grows and somehow gets into the main host, where it forms a mature individual. Some species can change up to four hosts. Maturation of each stage is possible only in suitable carrier organisms, as well as sexual reproduction. That is, the larvae of helminths, which have a host of ungulates, when they enter a predator or omnivore, can survive and develop into an adult, but they will not lay eggs. Helminths have an immunological relationship with the host organism, that is, they depend on the host’s immunity , and they themselves influence it, as a result of which they cannot live or develop in a different immune environment.

• Prevention includes washing hands before eating, thoroughly washing vegetables, fruits and berries, eaten raw, and heat-treating food.
• You can not contaminate the soil and water with feces.
• It is better to drink boiled water.
• Protect food from flies.
• If you suspect the presence of worms, consult a doctor.

1. Compulsory heat treatment of raw fish and meat consumed as food (or for pet food), especially of unknown origin (imported sushi , crabs , squid ).
2. It is advisable to refrain from swimming in contaminated fresh water bodies located near pastures, watering places for animals and other things. Avoid barbecue, barbecue and picnics in such places.
3. Regular examination and timely treatment of helminthiases will help to avoid conditions that threaten health and life.
4. Deworming of pets also reduces the risk of infection.
5. Thorough sanitization of household items for children, nurseries, toys, playgrounds and street animals (yard cats, dogs).
6. Fighting wild animals (precautionary rules when hiking in the forest, during hunting and fishing).
7. The destruction of domestic insects.
8. Fighting sewage discharges in small towns, with polluted reservoirs, with old landfills.
9. Thorough sanitary and hygienic processing of hands, food before use, places of residence and work (especially for employees of culinary shops) and kitchen items.

In a regular clinic, consult a therapist or parasitologist (private clinics). Helminthiasis treatment is a very extensive section. This includes a variety of nosological units: ascariasis and alveococcosis , cysticercosis and echinococcosis , trichinosis and schistosomiasis . In general practice, albendazole (nemazole), mebendazole (vermoxa) preparations are used for cestodes, levamzole, pyrantel, piperazine, as well as thiabendazole, ivermectin, avermectin - for nematodes and filariotoses, praziquantel, diethylcarbamtazamine and pristikarbatamazin - primer. To prevent the development of side effects of these drugs: with the development of anemia and for its prevention - methyluracil, leukomax, neopogen, leukostim, Vikasol - for the prevention of gastrointestinal bleeding and purulent-septic complications, due to the presence of parasites; B vitamins ( thiamine , cyanocobaclomin, in violation of the outflow of bile and liver function: ursosan , cholestyramine , methionine , colespitol , colestyramine , laxatives , enterosorbents , probiotics , antiallergic drugs , for the prevention of allergic reactions: suprastin, cetirizine, zetotifen and sleep disturbances.) If surgical treatment is not possible, plasmapheresis and hemoperfusion (with the development of severe toxic-allergic reactions) can play a role. With purulent-septic reactions: antimicrobial f (tinidazole, ornidazole), tetracyclines (doxycycline), sulfanilamides (sulfadimizine, sulfadiazine), lincosamides (clindamycin), macrolides (spiramycin, azithromycin) in combination with timely surgical intervention and recognition of the purulent-septic foci of gangrenum.

In severe cases: ephedrine preparations (broncholithin) / adrenaline - in case of allergic reactions: dexamethasone, betamethasone, beclamethasone, (the choice of the drug depends on the specific location of the parasites and the primary symptom complex: neuropsychiatric, allergic, anemic, arthralgic, asthmatic) and other corticosteroids. For the prevention of metabolic disorders: potassium orotate, insulin, aprotinin, pumpkin seed preparations (phenasal), pyroxan.

Some diseases are very difficult to differentiate and can easily be confused with oncological pathologies ( alveococcosis ), others are treated only surgically ( echinococcosis , alveococcosis , some tapeworms ), and others ( teniosis ) cannot be treated with tablets, because the patient will be infected with thousands of larvae - cysticercosis .

In the treatment of helminthiases, the timely recognition of the pathogen plays an important role. An important role is given to: a carefully collected history of the living / working conditions of the patient, contact with wild and domestic animals, an indication of the presence of anemia, night itching and other allergic reactions (including bronchial asthma during migration and reproduction of parasites), neuropsychiatric (in in case of pernicious anemia and follicular myelosis with diphyllobriotosis, sickle cell: with teniosis, teniarchosis), metabolic (especially with chronic cestodoses and trematodoses of the hepatobiliary zone and pancreas, p With echinococcosis and opisthorchiasis of this organ, diabetes mellitus can occur) and endocrine disorders (epidemic goiter, metabolic syndrome).

Helminthic invasion is often differentiated with other causes of these diseases.

Examples of drugs and the spectrum of their anthelmintic action

Depending on the type of helminths, the preparations may be different:

1. Preparations containing Mebendazole are used for enterobiasis , ascariasis , hookworm , strongyloidosis , trichocephalosis , trichinosis , teniosis , echinococcosis , multiple nematodes , alveococcosis , capillariosis , gnatostomza .
2. Preparations containing diethylcarbamazine - a means for treating various types of filariasis , including with damage to the lymphatic system , subcutaneous tissue and eye tissue.
3. Drugs containing Levamisole - used for ascariasis , hookworm infection , necatorosis , strongyloidosis , trichostrongyosis , trichocephalosis , enterobiosis , toxoplasmosis .
4. Befenia hydroxynaphthoate - against roundworms ( nematodes ) - with ascariasis , hookworm , trichostrongiasis ; trichocephalosis .
5. Piperazine adipate (does not kill roundworms , but paralyzes them) - is effective for ascariasis and enterobiasis .
6. Preparations containing Albendazole are most effective for cysticercosis and echinococcosis .
7. Preparations containing praziquantel are most effective for trematodoses , cestodoses , paragonimiasis , and schistosomiasis .

In any case, you should consult a doctor to prescribe treatment. Before using this or that remedy, be sure to read the contraindications!

According to the results of some studies, the presence of helminths in the human body is necessary for the normal development of the immune system , which is explained by the development of symbiosis with these organisms during the evolution of humans as a species . In accordance with this hypothesis, a side effect of deworming in the 20th century was a sharp increase in the incidence of eczema and other allergies ^[2] .

• Import of infectious diseases and parasites in the Russian Federation by labor migrants
• Deworming
• Helminthotherapy

• Yushkov V.F. Helminths of mammals . - Fauna of the European North-East of Russia. T. 3. - St. Petersburg. 1995.
• Shabunov A. A. , Radchenko N. M. Parasites of fish, amphibians and gull birds in the ecosystems of large reservoirs of the Vologda Oblast: monograph / Vologda State Technical University ; Rec .: N.A. Rybakova, I.V. Filonenko . - Vologda: VSTU, 2012 .-- 244 p. - ISBN 978-5-87851-462-0 .
• Jeremy Taylor Darwin Health: Why We Get Ill and How It Tells Evolution = Jeremy Taylor “Body by Darwin: How Evolution Shapes Our Health and Transforms Medicine”. - M .: Alpina Publisher, 2016 .-- 333 p. - ISBN 978-5-9614-5881-7 .

• Knipovich N.M. Worms // Brockhaus and Efron Encyclopedic Dictionary : in 86 volumes (82 volumes and 4 additional). - SPb. , 1890-1907.