Specific diseases classified as infectious include parasitosis. They are caused by special parasites that have adapted to life in or on the human body and feed and reproduce in it or with its help. In this case, humans can be both intermediate and definitive hosts for parasites (i. e. either eggs and larvae or adult individuals develop in the body). Depending on the type of parasites and the location of the lesion, many diseases caused by them can be identified. The most common are helminthiasis - diseases that arise from the parasitism of certain types of worms.
Parasites: various types of helminths in the body
The largest group of parasites that can live in the human body are various types of worms, both flat and round. They belong to a separate group of diseases, which doctors collectively call "helminthiases". Each parasite of this group has its own routes and methods of infection, features of the life cycle and development of clinical manifestations, as well as methods of its treatment. In addition, eachParasite, due to its life cycle, capable of causing specific complications. The most common parasites that can affect people are pinworms, roundworms, trichinae, pork or cattle tapeworms.
Types of parasites and features of the course of infection
If there are indirect signs of helminth infection, it can be assumed that one of the types of parasites lives in the person's body. However, for effective and correct treatment, it is important to know the specific types of parasites and which organs and systems they affect. To do this, it is important to undergo a comprehensive examination and pass a series of tests. Why is this necessary?
First of all, it is important to remember that different types of parasites live in the body of the host in the larval stage (if a person is its intermediate host) or as a sexually mature individual (if the definitive host). In this regard, the therapeutic effects may vary depending on the stage at which the worm parasitizes, as well as the habitat of the parasite.
Types of parasites such as echinococci are dangerous to humans in the larval stage. The larvae, in the form of a round cyst capsule filled with a toxic fluid, infect the lungs, liver, kidneys or brain. An echinococcal cyst containing larvae grows in these organs over many months or years. But such types of parasites as pinworms live in the body in the form of sexually mature individuals. Females crawl out of the rectum to lay millions of eggs, which are released into the external environment in feces.
Depending on the type of parasites, as well as the body's individual reactions to them, the location of the lesion and the body's response, clinical manifestations range from asymptomatic to pronounced and severe to death. It is also worth remembering that there are variants of mixed infections, in which several types of parasites live in the body at the same time.
How do parasites get into the body?
The way parasites enter the body can be different. Infection often occurs when parasite eggs enter the human body with contaminated food or water, through dirty hands, through broken skin, or through insect bites. Worm eggs often remain in the form of eggs in soil, water or on the surface of objects for a long time. When parasites enter the body through hands, food or water that have not been properly handled, they invade the body, where the eggs quickly mature and give rise to larvae (intermediate versions of the parasite) or adult individuals.
It is important to remember that parasites cause serious damage to the body even when there are no obvious signs of damage. First, they eat their host, depriving it of some nutrients, vitamins and minerals. In addition, parasites in the body greatly increase the body's allergenicity, overstimulate the immune system, which threatens the development of spontaneous skin and other allergic reactions to previously known products and substances.
The body does not remain indifferent to the penetration of worms, especially when it comes to soft tissues and internal organs. This causes protective inflammatory capsules to form in muscles and tissue, separating the parasite from healthy tissue. This leads to the formation of parasitic cysts, which are often filled with waste products from the worms. The body often reacts to the introduction of parasites with digestive disorders if they are worms living in the intestines, changes in appetite, weight fluctuations and the worsening of chronic diseases.
Do not think that the problem of parasites is relevant only for people from the poorest countries and those who pay attention to hygiene. The prevalence of helminths is astonishing; according to the WHO, it is comparable to diseases such as ARVI and influenza. Therefore, it is necessary to undergo regular examinations and rule out parasitosis.
Which parasite test is needed?
Many patients mistakenly believe that a single test for parasites (feces or a perianal swab) that shows a negative result is a guarantee of the absence of parasites in the body. However, in reality everything is not so, and this result means nothing. First, parasites can be extraintestinal and live in other organs and tissues, and then their eggs or larvae simply do not end up in the feces.
Second, at the time parasite tests are performed, there may be a period of time in the parasite's life when it is still laying eggs or not at all. And thirdly, there is a risk that not all requirements for the analysis are met and therefore the eggs simply will not be found in the sample provided.
So, if we are talking about intestinal worms, when prescribing a parasite test, feces are taken three times at certain intervals to confirm the presence or absence of parasites. Only this technique can confirm or refute the diagnosis with a probability of up to 90%.
In this regard, an analysis for parasites from a vein with the determination of antibodies against certain worms is more meaningful. If the body has recently come into contact with the parasite, class M antibodies are present against it, which identify the pathogen. If the parasite is present for a long time, antibodies of other classes are also produced.