Specific diseases classified as infectious include parasitosis. They are caused by special parasites that have adapted to life inside or on the human body, feeding and reproducing in it or with its help. In this case, a person can be both an intermediate and a definitive host for parasites (that is, 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 resulting from parasitism of special 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 the development of clinical manifestations, as well as methods of its treatment. In addition, each parasite is capable, due to its life cycles, of causing specific complications. The most common parasites that people can get sick with are pinworms and roundworms, trichinella, pork or bovine tapeworm.
Types of parasites and characteristics 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 treatment to be effective and correct, it is important to know the specific types of parasites, as well as which organs and systems are affected by them. To do this, it is important to undergo a full examination and pass a number of tests. Why is this necessary?
First of all, it is important to remember that various types of parasites live in the host’s body in a larval state (if a person is their intermediate host) or a sexually mature individual (if the final host). In this regard, the therapeutic effects, depending on what stage the worm is parasitizing, may be different, as well as the habitat of the parasite.
Types of parasites such as echinococcus will be dangerous for humans at the larval stage. The larvae, in the form of a round cyst capsule filled with a toxic liquid, infect the lungs, liver, kidneys or brain. Inside these organs, for many months or years, an echinococcal cyst grows, inside of which there are larvae. But such types of parasites as pinworms live in the body in the form of sexually mature individuals. Females crawl out of the rectum in order to lay millions of eggs, which are released into the external environment with 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, even fatal. It is also worth remembering that there are variants of mixed infections, when several types of parasites simultaneously live in the body.
How do parasites enter the body?
The ways parasites enter the body can be different. Infection often occurs when parasite eggs enter the human body with contaminated food or water, from dirty hands, as well as through damaged skin, through insect bites. Often, worm eggs remain for a long time in the form of eggs in soil, water or on the surfaces of objects. Entering the body through hands, food or water that has not undergone proper treatment, parasites penetrate into the body, where the eggs quickly ripen, and larvae (intermediate versions of the parasite) or mature individuals emerge from them.
It is important to remember that parasites in the body cause serious harm, even if there are no obvious signs of damage. First of all, they eat their host, depriving him of some nutrients, vitamins and minerals. In addition, parasites in the body sharply increase the allergenicity of the body, overstimulate the immune system, which threatens the development of spontaneous skin and other allergic reactions to previously quite familiar products and substances.
The body does not remain indifferent to the penetration of worms into it, especially if it is soft tissue and internal organs. Thus, protective inflammatory capsules are formed in muscles and tissues, separating the parasite from healthy tissues. This leads to the formation of parasitic cysts, often filled with waste products of worms. Often the body also reacts to the introduction of parasites with digestive disorders, if these are worms living in the intestines, changes in appetite, weight fluctuations and exacerbation of chronic diseases.
Do not think that the problem of parasites is relevant only for people from the poorest countries and those who are careless about hygiene. The prevalence of helminths is amazing; according to WHO, it is comparable to diseases such as ARVI and influenza. Therefore, it is necessary to undergo regular examinations and rule out parasitosis.
What kind of parasite test is needed?
Many patients mistakenly believe that a single test for parasites (feces or a smear from the perianal area), which 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 does not mean anything. Firstly, parasites can be extraintestinal, living in other organs and tissues, and then their eggs or larvae simply do not end up in the feces.
Secondly, at the time of taking tests for parasites, there may be a period of the parasite’s life when it still or no longer lays eggs. And thirdly, there is a risk that all the conditions for the analysis are not met, and therefore the eggs are simply not found in the sample that was provided.
Therefore, if we talk about intestinal worms, when a test for parasites is prescribed, feces are taken three times at a certain interval to confirm the presence or absence of parasites. Only this technique can confirm or refute the diagnosis with a probability of up to 90%.
More indicative in this regard is an analysis for parasites taken from a vein, with the determination of antibodies to certain worms. If the body has been in contact with the parasite very recently, there will be class M antibodies to it, which will identify the pathogen. Long-term presence of the parasite will also produce antibodies of other classes.