Specific diseases classified as infectious include parasitic diseases. They are caused by special parasites that have adapted to life in or on the human body, feeding and reproducing there or with its help. In this case, a person can be an intermediate and definitive host of parasites (that is, eggs and larvae or adult individuals develop in the body). Depending on the type of parasite and the location of the lesion, many diseases caused by them can be identified. The most common are helminthiasis - diseases resulting from the 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, flat and round. They belong to a separate group of diseases, which doctors collectively call "helminthiases". Each parasite in 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 their treatment. Furthermore, each parasite is capable, due to its life cycles, of causing specific complications. The most common parasites that can make people sick are pinworms and roundworms, trichinella, pork or bovine tapeworm.
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 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 full examination and pass several tests. Why is this necessary?
First of all, it is important to remember that several types of parasites live in the host's body in a larval state (if the person is its intermediate host) or in a sexually mature individual (if it is the final host). In this sense, the therapeutic effects, depending on the stage at which the worm is parasitizing, may be different, as well as the parasite's habitat.
Types of parasites such as echinococcus are dangerous to humans in 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 which there are larvae. But types of parasites, such 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 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 live simultaneously in the body.
How do parasites enter the body?
The ways in which parasites enter the body can be different. Infection usually occurs when parasite eggs enter the human body with contaminated food or water, through dirty hands, as well as through damaged skin, through insect bites. Often, worm eggs remain in the form of eggs for a long time in the soil, water or on the surface of objects. Entering the body through hands, food or water that have not undergone adequate treatment, the parasites penetrate the body, where the eggs mature quickly 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 damage, even if there are no obvious signs of damage. Firstly, they eat the host, depriving it of some nutrients, vitamins and minerals. In addition, parasites in the body sharply increase the allergenicity of the body, excessively stimulate the immune system, which threatens the development of spontaneous skin and other allergic reactions to previously quite familiar products and substances.
The body is not indifferent to the penetration of worms, 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 worm waste. Often, the body also reacts to the introduction of parasites with digestive disorders, if they are worms that live in the intestines, changes in appetite, weight fluctuations and exacerbation of chronic diseases.
Do not think that the problem of parasites is only relevant for people in the poorest countries and for those who are careless about hygiene. The prevalence of helminths is incredible, according to the WHO it is comparable to diseases such as ARVI and influenza. Therefore, it is necessary to carry out regular examinations and rule out parasites.
What type of parasite test is needed?
Many patients mistakenly believe that a single parasite test (stool or swab from the perianal region), which presents a negative result, is a guarantee of the absence of parasites in the body. However, in reality, not everything is like that and this result means nothing. 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, when testing for parasites is carried out, there may be a period in the life of the parasite in which it still lays or no longer lays eggs. And thirdly, there is a risk that all the conditions for the analysis will not be met, and therefore eggs will simply not be found in the provided sample.
Therefore, if we talk about intestinal worms, when a parasite test is prescribed, feces are collected 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 sense is the analysis of parasites taken from a vein, with the determination of antibodies against certain worms. If the body has been in contact with the parasite very recently, there will be class M antibodies against it, which will identify the pathogen. The prolonged presence of the parasite will also produce antibodies from other classes.