Parasitic diseases are a wide and diverse group of diseases caused by helminths and protozoa that travel through the life cycle of 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 quite difficult to suspect and recognize them.
How does the infection occur?
Before entering the human body, helminths and protozoa go through a developmental cycle in other environments or living organisms.
- Roundworm, strongyloid and hookworm eggs and larvae remain in the soil under certain conditions of temperature and humidity. A person becomes infected when contaminated soil enters through dirty hands, water, unwashed fruits and vegetables, directly from the soil.
- In living organisms, the following helminths undergo developmental cycles: opisthorchis (cat worm), clonorchis, trichinella, toxocara, echinococcus, porcine and bovine tapeworm. Before reaching maturity, to parasitize on a person, it is possible to change one or two intermediate hosts. They are molluscs, crustaceans, fish, insects. Eating poorly thermally processed fish and meat, raw water leads to infection.
Another form of infection is through direct contact with people through handshakes, hygiene items and common household utensils or through self-infection. We are talking about contagious helminths: enterobiasis, strongyloidosis, cysticercosis, giardiasis.
How to suspect a parasitic disease?
Manifestations can be varied, from mild to severe. There are rarely signs typical of a specific pathogen. Often there are no signs, or they disguise themselves as other diseases, or they disappear with the end of a parasite development cycle and the beginning of another. For example, ascaris larvae first enter 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 parents.
However, the acute and chronic phases of the parasitic disease course are usually differentiated.
Acute manifestations occur as a result of a general effect on the body:
- The effects of toxins - temperature rise up to 37-37, 5 degrees, weakness, headaches, decreased mood and performance, sleep disturbances;
- Allergic reactions - itching, hives, bronchospasm, shortness of breath, less frequently 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, each helminth can see attachment devices on the body, injuring 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 of the time, the intestine suffers, the prolonged mechanical action leads to its inflammation, decreased absorption and digestion of food. Anemia develops, lack of vitamins and minerals and, in young children, there is a delay in growth and weight gain. The gallbladder and biliary tract (giardiasis) may be affected; cardiovascular system, lungs, nervous system (usually trichinosis); lungs and liver (echinococcosis) and so on. Over the long haul, immunity is suppressed and secondary infections join.
Therefore, we have many forms of infection, development mechanisms and manifestations of parasitic diseases. Turns out every second person runs the risk of getting sick, right? But sometimes helminths may not remain in the body: they die and depart, or 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. Most susceptible to developing helminthiasis are children under 5 years of age, actively learning the world "in the language" and people with chronic illnesses and weakened immunity.
If you find any of the signs listed, have a clinical blood test with a white blood cell count. An increase in eosinophils of up to 7-10% or more will become another suspicious criterion.
How to identify a parasitic disease?
The criterion for disease activity is egg detection! This means the passage of the helminths development cycle in the organism, its parasitism and reproduction. These are mainly intestinal helminthiasis, when a person is the ultimate 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 developmental cycle, so a single study is not enough. If the result is negative, a three-time study is recommended with an interval of 3-7 days;
- 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 confuse the host and cannot develop further. In these cases, eggs will never appear in the stool, the disease can only be detected by antibody determination.
What should you pay attention to?
- The presence of manifestations and simultaneous detection of IgG may indicate a chronic phase of helminthiasis;
- In doubtful cases, it is recommended to retest the IgG after 2 weeks. A 2-fold or more rise in antibody level indicates helminth activity;
- In trichinosis, echinococcosis, and cysticercosis, the determination of antibodies is the only possible method of laboratory diagnosis, since the individual is an intermediate host of these helminths.
For your convenience, a complex "Diagnosis of parasitic diseases" was created, which includes a clinical blood test, total IgE (allergic component) and the determination of antibodies to the most common helminths and protozoa.