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Parasitic infections: causes, symptoms.

Parasitic infections represent a wide range of symptoms and diseases caused by the entry of eggs or adult parasites into the human body.Often, the first signs of the disease can only be detected after several days, or even months, or even years in some cases.This is due to the life cycle of parasites and their main functions: good camouflage and maintaining their own life by receiving nutrients from the host's body.

Types of parasites and their characteristics

Parasitic infections, depending on certain properties of their manifestation, are divided into three groups:

  1. Ectoparasites.
    The main location is the surface of the human body.These include lice, fleas, ticks and bedbugs.They feed primarily on human blood, although in some cases, such as in demodicosis mites, their primary food is the secretion of dead sebaceous glands or epithelial (skin) cells.EctoparsitesThe first signs of a parasitic infection are quite easy to recognize, as they cause itching and burning in their habitats.Some ectoparasites carry serious diseases: typhus, anthrax, encephalitis and trypanosomiasis.They cause enormous damage to human health, even death.
  2. Endoparasites (protozoa).
    Mainly affects internal organs.They are unicellular in structure, hence the name protozoan.Despite this, they can cause serious forms of illness.The main diseases in this group are parasitic blood infections caused by toxoplasma and intestinal infections caused by amoeba or giardia.
  3. Helminths.
    These are the causative agents of the most common forms of parasitic infections.In the human body, their development cycles take place mainly in the intestines and tissues, where the manifestation of symptoms of the disease begins.

Roundworms (nematodes)

These are parasites whose bodies are round in cross section.Sexual characteristics are easily distinguishable.Females are generally larger than males.But representatives of this class also have hermaphrodites.All nematodes go through stages of development: egg, larva and adult.This class includes:

  1. Pinworm.The disease is caused by enterobiasis.It mainly affects preschool and primary school children.
  2. Whipworm.Causes trichuriasis disease.Has a distinctive body shape.2/3 of the body length has a thin diameter, reminiscent of human hair or thread.The other end of the body has a larger diameter and contains the intestines.
  3. Roundworm.The disease is caused by ascariasis.Adults reach sizes of 25 cm (males) and 40 cm (females).Once the larva enters the human body, it passes through the stomach and enters the small intestine.From there, through the pores of the blood flow, it enters the liver, then the heart and finally the lungs, where it develops within 7-10 days.Then the larvae begin to move up to the larynx.Once they arrive in the oral cavity, they are re-swallowed.Once in the small intestine, the larvae cannot re-enter the bloodstream through the pores due to their large size.There they become adults in 2-3 months.After that, reproduction begins and the cycle repeats.The female can lay more than 200,000 eggs per day.
Roundworms

Tapeworms (cestodes)

They are parasites whose body resembles the shape of a ribbon.A distinctive feature of this class is the absence of a digestive system.These include:

  1. Echinococcus.The disease is caused by echinococcosis.This parasite is small (2 to 9 mm) and consists of several segments and suckers.The uterus of a sexually mature individual contains a large number of eggs in which larvae are located.The main locations of echinococci are the liver and lungs.There it causes a chronic condition called hydatid cyst.
  2. Bull tapeworm.Causes the disease taeniarinchiasis.In the larval stage, it has an intermediate host: livestock.Once in the human body, it develops in the small intestine to the band stage.The body of an adult parasite has up to 1,000 segments and can reach 4 to 10 meters in length.
  3. Pork tapeworm.Causes the disease taeniasis.Outwardly, it is very similar to the bull tapeworm.It also has intermediate hosts: pigs, dogs, camels, hares and rabbits.In humans, it is an intestinal parasite.The size of an adult individual does not exceed 4 meters in length.
  4. The tapeworm is large.The disease is caused by diphyllobothriasis.Lives in freshwater bodies of water.It uses crustaceans and fish as intermediate hosts.In the human body, it parasitizes the small intestine.An adult can reach several meters in length.

Flatworms (flukes)

During their life cycle, these parasites can change several intermediate hosts.In humans, they can be parasitized in any organ.This group includes:

  1. Schistosomes.The disease is caused by schistosomiasis.They can enter the human body through contact with contaminated fresh water.The parasite penetrates the skin and enters the circulatory system, where it begins to actively multiply.Females can produce 300 to 3,000 eggs per day.In addition, with blood circulation, eggs spread throughout the body and continue development in any organ.Their body length does not exceed 0.1-0.2 cm.
  2. Liver flukes.The disease is caused by opisthorchiasis.The length of an adult varies from 3 to 5 cm.When it enters the human body, it parasitizes the bile ducts, gallbladder, liver and pancreas.It is fixed in these organs using suction cups located on the body.
Liver flukes

Ways of penetration of parasites into the human body

  1. The nutritional route of infection is considered the most common.A person becomes infected with the parasite by eating poorly washed vegetables and fruits.Meat that has not undergone sufficient heat treatment is particularly dangerous.In addition, a person becomes infected with a parasitic infection if personal hygiene rules are not followed.For example, not washing your hands before eating.
  2. Transplacental route.The parasitic infection is transmitted from the pregnant woman to the child through the placenta.These include, for example, diseases such as toxoplasmosis, malaria or hookworm.
  3. Percutaneous route.The parasite enters the human body through the skin.These are mainly schistosomes and hookworms.
  4. Contact path.The parasite is transmitted through dirty hands, contaminated personal belongings and underwear.This is how lice, scabies and pinworms are most often transmitted.
  5. Transmission path.Infection occurs after the bite of insects carrying parasites.For example, malaria.

Symptoms

Many parasitic diseases have no symptoms in the early stages.This is due to the developmental stages of the pathogen.Each type of parasite manifests itself differently as it grows.Common general symptoms of a parasitic infection include:

  1. Itching.
  2. Redness of the skin like hives.
  3. Diarrhea.
  4. Constipation.
  5. Flatulence.
  6. Nausea, vomiting.
  7. Spasms and pain in the gastrointestinal tract.
  8. Lose weight without dieting or increased physical activity.
  9. Feverish state.
  10. High body temperature (38-40 ˚C) for a long time.
  11. Prolonged attacks of dry cough.
  12. Enlarged lymph nodes.
  13. Painful sensations in the muscles.
  14. Psycho-emotional disorders.

Diagnosis

Diagnosis

If you suspect the presence of parasitic diseases, you must undergo a series of tests.The diagnosis of parasitic infections makes it possible to determine the presence or absence of a parasite, its type and its location in the body.The data obtained will help the doctor make the correct diagnosis and prescribe the appropriate treatment.

Diagnostic methods include:

  1. Stool examination.Allows you to determine the presence of most types of parasites living in the intestines.Their eggs, larvae and body segments are excreted in the feces.There are two types of analysis:
    1. A stool sample is examined for helminth eggs and larvae.The analysis is delivered to the laboratory, where the doctor takes smears and examines them under a microscope.This method is often used, but it is not precise enough.In order to make a final diagnosis, the patient must undergo this test up to three times at short intervals.This is due to the parasite life cycle and egg laying, detected by this research method.
    2. Scraping (washing) the folds of the anus.This test is used to detect only one type of helminth: pinworms.Parasitic infections are more common in children than adults.It is for this reason that this analysis is carried out mainly for children.The lab technician moistens a cotton swab or glass eye pad in water or glycerin and rinses it from the perianal folds.Then the resulting material is applied to a glass slide and examined under a microscope.This analysis is also done using a different method: a laboratory technician sticks a piece of adhesive tape to the anal passage, presses it and peels it off.The adhesive tape is then stuck to a glass slide and also observed under a microscope.The parasite is diagnosed quite accurately.Thanks to these methods, the laboratory technician is able to examine not only helminth eggs, but sometimes also adult individuals.
  2. Examination of cerebrospinal fluid, sputum, duodenal contents (bile), urine.Prescribed based on the results of a survey of patients to determine the presence of the parasite and determine its location.These biological fluids are analyzed by microscopy and macroscopy.First, the obtained sample is examined for the presence of adult individuals, then microscopy is carried out to detect eggs and larvae of parasites.
  3. Blood test.Modern methods of blood testing for parasitic infections make it possible to determine with high accuracy the presence and type of pathogen.Three types of such diagnostics are used:
    1. Serological reactions.Used to determine the presence of antiparasitic antibodies in the patient's blood serum.This method is considered highly specific, but inferior to PCR diagnostics.
    2. PCR diagnosis.This method is based on the identification of parasite DNA in any biological fluid collected for analysis.
    3. Genetic research.This involves detecting the genome of the parasite in a patient's blood sample.This method is used much less frequently than all the others, but it is very accurate.
  4. Examination of biopsy material and lymph nodes.For this analysis, the doctor excises a small section of an organ, tissue, or entire lymph node and sends it for histological examination.In this way, the presence or absence of parasites is diagnosed.

Recommendations for test preparation

Before taking tests for parasitic infections, you must prepare properly.If the recommendations are followed, the diagnostic accuracy increases, since the material does not contain interfering factors affecting the effectiveness of research methods.

Preparing for a stool test:

  1. Antibiotics, anti-inflammatories and antacids should be stopped.The use of drugs and other drugs containing bismuth and iron is also unacceptable.
  2. If a barium x-ray examination or colonoscopy was performed, during which an enema was performed to cleanse the intestines, a stool test can be carried out only after 2-3 days.
  3. It is not recommended to give stools if menstrual bleeding begins or hemorrhoids worsen.

Preparing for a blood test:

  1. It is necessary to stop taking pharmacological drugs that affect the blood count.
  2. Three days before the test, you should follow a light diet, not eat fatty foods and give up alcohol.
  3. A blood test to detect parasitic infections is taken on an empty stomach.Drinking a small amount of clean water is permitted.

For other tests, most often no special preparation is required.You just need to follow the doctor's recommendations.

Treatment

Unfortunately, symptoms of parasitic infections cannot always be detected in the early stages of the disease.In such cases, treatment begins late.It is important to understand: the longer the parasite stays in the body, the more difficult it will be to get rid of it.

The treatment of infectious and parasitic infections is divided into two areas:

  1. Symptomatic treatment.Intended to eliminate clinical manifestations of the disease.These include a decrease in body temperature, elimination of redness and itching, and normalization of the functioning of the gastrointestinal tract.
  2. Etiological treatment of parasitic infections aims to eliminate the causative agent of the disease.

In some cases, surgery may be necessary.It applies to alveococcosis, echinococcosis and some types of trematode infection.

When the body is dehydrated, solutions containing salt are prescribed.

Only a doctor can prescribe treatment for parasitic infections based on laboratory tests and patient interviews.

Prevention

It is very important to observe the prevention of parasitic infections.In most cases, this will help prevent pathogens from entering the body.

Prevention

Preventive measures include:

  1. Compliance with the rules of personal hygiene: you must wash your hands before eating, after using the toilet and when returning from the street.
  2. Vegetables and fruits should be washed well.
  3. It is imperative to carry out sufficient heat treatment of meat, fish and seafood.
  4. Tap water should not be used as drinking water, as it is not always free of parasites.Using household filters as additional cleaning will not help.The best option would be to drink boiled or bottled water.
  5. If pets live at home, they should be dewormed once every six months.You should also limit contact with your pet if it shows signs of parasitic diseases and contact a veterinary clinic.
  6. You should iron underwear (especially children's) after washing it.
  7. After visiting exotic countries, when working on land, as well as for employees of children's institutions, it is recommended to be examined once a year for the presence of parasitic infections and, if necessary, to carry out prophylaxis with medications.