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 multiplying in it or with its help. In this case, a person can be both an intermediate and a final host for parasites (that is, either eggs and larvae or adults 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 caused by parasitism of special types of worms.
Parasites: different 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 "helminthiasis". Each parasite of this group has its own routes and methods of infection, characteristics of the life cycle and development of clinical manifestations, as well as methods of its treatment. In addition, eacha parasite is capable, because of its life cycle, of causing specific complications. The most common parasites that people can get sick from are pinworms and roundworms, trichinella, pig or cattle 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 human body. However, in order for the 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 complete examination and pass a number of tests. Why is this necessary?
First of all, it is important to remember that different types of parasites live in the host's body in a larval state (if a human is their intermediate host) or a sexually mature individual (if a final host). In this regard, the therapeutic effects, depending on the stage of parasite infestation of the worm, can be different, as well as the habitat of the parasite.
Parasite species such as echinococci will be dangerous to humans in the larval stage. The larvae, in the form of a round cyst-like 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 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 to lay millions of eggs, which are released into the environment in the feces.
Depending on the type of parasites, as well as individual reactions of the body to them, the location of the lesion and the reaction of the body, clinical manifestations vary 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 live in the body at the same time.
How do parasites enter the body?
The ways in which 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 the soil, water or on the surfaces of objects. Entering the body through hands, food or water that has not been properly processed, the parasites penetrate the body, where the eggs quickly mature and hatch into larvae (intermediate versions of the parasite) or adults.
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 it 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 well-known products and substances.
The body does not remain indifferent to the penetration of worms into it, especially when it comes to soft tissues and internal organs. Thus, protective inflammatory capsules are formed in muscles and tissues, which separate the parasite from healthy tissues. This leads to the formation of parasitic cysts, often filled with worm waste products. Often the body also reacts to the introduction of parasites with digestive disorders, if these are worms living in the intestines, changes in appetite, fluctuations in weight and exacerbation of chronic diseases.
Do not think that the problem of parasites is only relevant for people in the poorest countries and those who do not take care of hygiene. The prevalence of helminths is incredible, according to the WHO, it is comparable to diseases such as ARVI and influenza. That is why it is necessary to undergo regular examinations and to rule out parasitosis.
What kind of parasite test is needed?
Many patients mistakenly believe that a parasite test (stool or smear from the perianal area) showing 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, living in other organs and tissues, and then their eggs or larvae simply do not fall into the feces.
Second, at the time of parasite testing, there may be a period in the parasite's life when it is still or no longer laying 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 provided sample.
Therefore, if we are talking about intestinal worms, when a parasite test is prescribed, stool is taken three times at a certain interval to confirm the presence or absence of parasites. Only this technique can confirm or reject the diagnosis with a probability of up to 90%.
More indicative in this regard is the analysis for parasites taken from the 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 that will identify the pathogen. Long-term presence of the parasite will also produce antibodies of other classes.