Parasitic diseases are a wide, diverse group of diseases caused by helminths and protozoa that go through the life cycle of the human body, feed and multiply at the expense of the "host" and damage various organs and systems. Given the effect on the whole body, they are quite difficult to suspect and recognize.
How does the infection occur?
Before entering the human body, helminths and protozoa undergo a developmental cycle in other environments or living organisms.
- Eggs and larvae of roundworms, strongyloids, hookworms remain in the soil under certain temperature and humidity conditions. Man becomes infected when contaminated soil enters the ground directly through dirty hands, water, unwashed fruits and vegetables.
- In living organisms, the following helminths go through a developmental cycle: opisthorchis (cat fluke), clonorchis, trichinella, toxocara, echinococcus, swine, and bovine tapeworm. Before reaching maturity, in order to be able to parasitize a person, it is possible to exchange one or two intermediate hosts. These are mollusks, crabs, fish, insects. Consumption of improperly heat-treated fish and meat leads to raw water infection.
Another way of infection is through direct contact of people with handshakes, shared hygiene and household items, or self-infection. We talk about infectious helminths: enterobiasis, strongyloidosis, cysticercosis, giardiasis.
How is a parasitic disease suspected?
Manifestations can vary from mild to severe. Rarely are there typical signals that release a particular pathogen. Often there are no signs or they disguise themselves as another disease or disappear when one cycle of parasite development ends and another begins. For example, ascaris 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) that does not alarm the parent.
However, the acute and chronic stages of the course of a parasitic disease are generally distinguished.
Acute manifestations occur as a result of general effects on the body:
- Effects of toxins - a temperature rise of 37-37, 5 degrees, weakness, headache, decreased mood and performance, sleep disturbances;
- Allergic reactions - itching, hives, 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, all helminths show the tools needed to fix them in the body and damage the mucous membranes: teeth, hooks, suction cups. This results in abdominal pain, frequent bowel movements and dyspepsia.
The chronic phase is characterized by damage to certain organs and systems. Most often, the intestines suffer, leading to inflammation of prolonged mechanical effects, impaired absorption and digestion of food. Anemia, vitamin and mineral deficiencies develop, and growth and weight gain are delayed in young children. The gallbladder and bile ducts (giardiasis) may be affected; cardiovascular system, lungs, nervous system (usually trichinosis); lung and liver (echinococcosis) and so on. With long-term treatment, immunity is suppressed and secondary infections join.
So there are many modes of infection, developmental mechanisms and manifestations of parasitic diseases. It turns out that every second person is at risk of getting sick, right? But sometimes helminths may not stay in the body: they die and leave, or they pass "without passing" without starting to parasitize (therefore, the detection of a "worm" in the stool does not prove the presence of the disease). Much depends on the stage of helminth, its invasive properties, and the human immune system. Children under the age of 5 who are actively learning the world "in their language" as well as those with chronic diseases and weakened immunity are more susceptible to the development of helminthiasis.
If you find any of these signs, perform a clinical blood count with a leukocyte count. An increase of 7-10% or more in eosinophils will be another suspicious criterion.
How to identify a parasitic disease?
- Examination of the faeces of the eggs of protozoa and helminths, preferably the method of enrichment - PARASEP Determines the eggs of all types of helminths and protozoa in the gut
The criterion for disease activity is the detection of oocytes! This means that the developmental cycle, parasitism and reproduction of helminth in the body pass through. These are primarily intestinal worms where a person is the ultimate host, the "permanent residence" of the parasite, and the eggs are needed for further spread and the start of the next cycle.
Pay attention to the following points:
- Each helminth has its own developmental cycle, so a single study is not enough. If the result is negative, a triple test is recommended at 3-7 day intervals;
- There are forms of helminthiasis where a person is an intermediate host (carrier of helminth larvae) or a "biological dead end" where the larvae have confused the host and cannot develop further at all. In such cases, the eggs never appear in the feces, the disease can only be detected by determining antibodies.
- Scratching test for enterobiasis - only pinworm oocytes are detected in the perianal folds. Female pinworms lay eggs, leaving the intestines only at night when the man relaxes. Therefore, the test is performed strictly after sleep before washing!
- Examination of lamblia antigen in faeces 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 (immunoglobulins) against helminths is aimed at evaluating the immune system against pathogens. Basically, the most persistent immunoglobulins are defined - class G (IgG), reflecting the fact of infection, but do not allow to understand whether there is now a helminth in the body or not, because IgG is stored in the body for a long time in the "memory archive". .
What is worth paying attention to?
- The presence of manifestations and the simultaneous detection of IgG may indicate a chronic phase of helminthiasis;
- In case of doubt, re-testing of IgG after 2 weeks is recommended. A doubling or greater increase in antibody levels indicates helminth activity;
- In the case of trichinosis, echinococcosis, cysticercosis, the determination of antibodies is the only possible laboratory diagnostic method, as a person is the intermediate host of these helminth samples.
For your convenience, a complex "Diagnosis of Parasitic Diseases" has been developed that includes clinical blood testing, total IgE (allergic component), and detection of antibodies to the most common helminths and protozoa.