Parasitic diseases are a widespread, diverse group of diseases caused by helminths and protozoa that go through the life cycle in the human body, feeding and multiplying at the expense of the "host", and damaging various organs and systems. Given the effect they have on the whole body, it is rather difficult to suspect and recognize them.
How does the infection work?
Before entering the human body, helminths and protozoa go through a development cycle in other environments or living organisms.
- Eggs and larvae of roundworms, strongyloids, hookworms remain in the soil under certain conditions of temperature and humidity. A person becomes infected when contaminated soil comes directly from the soil through dirty hands, water, unwashed fruits and vegetables.
- The following helminths go through developmental cycles in living organisms: Opisthorchis (cat leech), Clonorchis, Trichinella, Toxocara, Echinococcus, pork and beef tapeworm. To parasitize a person, before reaching maturity, it is possible to switch one or two intermediate hosts. These are mollusks, crustaceans, fish, insects. The consumption of insufficiently thermally processed fish and meat and raw water leads to infections.
Another type of infection is direct contact with people through handshakes, common hygiene and household items, or through self-infection. We are talking about contagious helminths: enterobiasis, strongyloidosis, cysticercosis, giardiasis.
How can a parasitic disease be suspected?
The manifestations can be varied, from easy to severe. There are seldom typical signs that indicate a certain pathogen. Often times there are no signs, or they disguise themselves as other diseases, or disappear when one development cycle of the parasite ends and another begins. Ascaris larvae, for example, first enter the human lungs, where they mature and migrate to the intestines. The child may be disturbed by a brief cough (similar to a cold) that does not worry the parents.
Nevertheless, as a rule, a distinction is made between acute and chronic phases in the course of the parasitic disease.
Acute manifestations occur as a result of a general effect on the body:
- The effects of toxins - temperature increase to 37 - 37, 5 degrees, weakness, headache, poor mood and performance, sleep disorders;
- Allergic reactions - itching, urticaria, bronchospasm, shortness of breath, less often Quincke's edema;
- Activation of the immune system - muscle and joint pain; enlarged lymph nodes, liver, and spleen;
- Mechanical impact - if you look under a microscope, any helminth can see devices for fastening in the body that injure the mucous membrane: teeth, hooks, suction cups. The result is abdominal pain, frequent bowel movements, and dyspepsia.
The chronic phase is characterized by damage to certain organs and systems. Most often the intestine suffers, prolonged mechanical exposure leads to inflammation, impaired absorption and digestion of food. Anemia, a lack of vitamins and minerals develops, and there is a delay in growth and weight gain in young children. Gallbladder and biliary tract (giardiasis) can be affected; Cardiovascular system, lungs, nervous system (usually trichinosis); Lungs and liver (echinococcosis) and so on. With a long course, immunity is suppressed and secondary infections join.
So we have many routes of infection, development mechanisms and manifestations of parasitic diseases. It turns out that every second person is at risk of disease, right? But sometimes helminths do not stay in the body: die and go or pass "on the go" without parasitizing (which is why the detection of a "worm" in the feces does not prove the presence of the disease). Much depends on the stage of the helminth, its invasive properties, and the human immune system. More susceptible to developing helminthiasis are children under the age of 5 who are actively learning the world "on the tongue" and people with chronic diseases and weakened immunity.
If you find any of the signs listed, do a clinical blood test with a white blood cell count. An increase in eosinophils of up to 7-10% or more becomes a further criterion for suspicion.
How do you recognize a parasitic disease?
- The study of feces for protozoa and helminth eggs, preferably the enrichment method - PARASEP determines the eggs of all types of helminths and protozoa that live in the intestine
The criterion for disease activity is the detection of eggs! This means the passage of the cycle of development of the helminth in the body, its parasitism and reproduction. These are mainly intestinal helminthiases in which a person is the ultimate host, the "permanent abode" of the parasite, and eggs are necessary for further spread and the start of the next cycle.
You should pay attention to the following points:
- Each helminth has its own development cycle, so a single study is not enough. If the result is negative, a three-time examination with an interval of 3-7 days is recommended;
- There are such forms of helminthiasis when a human is an intermediate host (vector of helminth larvae) or a "biological impasse", when the larvae have confused the host and are unable to develop at all. In such cases, eggs will never appear in the feces thatDisease can only be detected by determining antibodies.
- Examination of the scraping for enterobiasis - shows only pinworm eggs in the perianal folds. Female pinworms lay eggs and only leave the intestines at night when a person is relaxed. Therefore, the study is carried out strictly after sleeping, before washing!
- Examining the lamblia antigen in feces is a highly precise method of detecting lamblia. For better detection, it is recommended that a choleretic diet be followed before the test.
- The study of antibodies against helminths (immunoglobulins) aims to assess the immune system against pathogens. Basically, the most stubborn immunoglobulins are determined - class G (IgG), which reflects the fact of an infection, but does not make it possible to determine whether there is a helminth in the body or not, since IgG is stored in the body for a long time in the "memory archive".
What should you watch out for?
- The presence of manifestations and the simultaneous detection of IgG may indicate a chronic phase of helminthiasis;
- If in doubt, it is recommended to test IgG again after 2 weeks. An increase in the antibody level by two or more times indicates the activity of the helminth;
- In the case of trichinosis, echinococcosis, cysticercosis, the determination of antibodies is the only possible method of laboratory diagnostics, since humans are intermediate hosts for these helminths.
For your convenience, a complex "Diagnostics of Parasitic Diseases" has been created, which includes a clinical blood test, total IgE (allergic component) and the determination of antibodies against the most common helminths and protozoa.