Parasitic diseases are a widespread and diverse group of diseases caused by helminths and protozoa that go through the life cycle in the human body, feeding and reproducing at the expense of the "host" and causing damage to various organs and systems. Given the effect on the whole body as a whole, it is rather difficult to suspect and recognize them.
How does the infection happen?
Before entering the human body, helminths and protozoa go through a development cycle in other environments or living organisms.
- Eggs and larvae of nematodes, strongyloids, ankyloids remain in the soil under certain conditions of temperature and humidity. A person becomes infected when contaminated soil enters through dirty hands, water, unwashed fruit and vegetables, directly from the soil.
- In living organisms, the following helminths undergo development cycles: opisthorchis (cat fluke), clonorchis, trichinella, toxocara, echinococcus, pork and bovine tapeworms. Before reaching maturity, to parasitize in a person, it is possible to change one or two intermediate hosts. These are mollusks, crustaceans, fish, insects. By eating insufficiently heat-treated fish and meat, raw water leads to infection.
Another way of infection is through direct contact of people through handshakes, common hygiene and household items, or by self-infection. We are talking about contagious helminths: enterobiasis, strongyloidosis, cysticercosis, giardiasis.
How can a parasitic disease be suspected?
Manifestations can be varied, from mild to severe. There are rarely typical signs that emit a specific pathogen. Often there are no signs, either they disguise themselves as other diseases, or they disappear when one cycle of parasite development ends and another begins. For example, roundworm larvae first enter the human lungs, where they mature and migrate to the intestines. The child may be bothered by a short cough (similar to a cold), which does not alarm the parent.
However, the acute and chronic stages of the course of the parasitic disease are usually distinguished.
Acute manifestations occur as a result of a general effect on the body:
- The effects of toxins - an increase in temperature up to 37 - 37, 5 degrees, weakness, headache, decreased mood and performance, sleep disturbances;
- Allergic reactions - itching, urticaria, bronchospasm, shortness of breath, less often Quincke's edema;
- Activation of the immune system - muscle and joint pain; swollen lymph nodes, liver and spleen;
- Mechanical impact - if you look under the microscope, each helminth can see devices for fastening in the body, injuring the mucous membrane: teeth, hooks, suckers. 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 action leads to its inflammation, impaired absorption and digestion of food. Anemia, lack of vitamins and minerals develops, and in young children there is a delay in growth and weight gain. The 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.
Thus, we have many ways of infection, mechanisms of development and manifestations of parasitic diseases. It turns out that one in two people are at risk of getting sick, right? But sometimes the helminths may not stay in the body: they die and go, or they pass "in passing" without starting to parasitize (which is why the detection of a "worm" in the stool 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 the development of helminthiasis are children under 5, who actively learn the world "on the tongue" and people with chronic diseases and weakened immunity.
If you find any of the signs listed, take a clinical blood test with a white blood cell count. An increase in eosinophils of up to 7-10% or more will become another suspect criterion.
How to identify 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 living in the intestine
The criterion for disease activity is egg detection! This means the passage of the development cycle of the helminth in the body, its parasitism and reproduction. These are mainly intestinal helminthiasis, when a person is the final host, the "permanent residence" of the parasite and eggs are needed 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-fold study with an interval of 3-7 days is recommended;
- There are such forms of helminthiasis, when a person is an intermediate host (carrier of helminth larvae) or a "biological dead end", when the larvae have confused the host and cannot develop further. In such cases, the eggs will never appear in the stool, the disease can only be detected by determining antibodies.
- Scraping examination for enterobiasis - reveals only pinworm eggs in the perianal folds. Female pinworms lay eggs, leaving the intestines exclusively at night, when a person is relaxed. Therefore, the study is carried out strictly after sleep Before washing!
- The study of lamblia antigen in feces is a high-precision method for the detection of lamblia. For better detection, it is recommended to follow a choleretic diet before testing.
- The study of antibodies against helminths (immunoglobulins) is aimed at evaluating the immune system against pathogens. Basically, the most persistent immunoglobulins are determined - class G (IgG), which reflects the fact of the infection, but does not make it possible to understand whether there is a helminth in the body now or not, since IgG is stored in the body for a long time time in the "memory archive".
What should you pay attention to?
- The presence of manifestations and the simultaneous detection of IgG may indicate a chronic stage of helminthiasis;
- In doubtful cases, it is recommended to repeat the IgG test after 2 weeks. An increase in the level of antibodies by 2 times or more indicates the activity of the helminth;
- With trichinosis, echinococcosis, cysticercosis, the determination of antibodies is the only possible method of laboratory diagnostics, since a person is an intermediate host for these helminths.
For your convenience, a complex "Diagnostics of parasitic diseases" has been formed, which includes a clinical blood test, total IgE (allergic component) and the determination of antibodies to the most common helminths and protozoa.