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Parasitic infections: causes, symptoms.

Parasitic infections represent a diverse range of symptoms and diseases that are caused by the entry of eggs or adult parasites into the human body.Often, the first signs of the disease cannot be detected for several days, and in some cases, several months or even years.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 predominantly on human blood, although in some cases, such as with mites that cause demodicosis, the main food is the secretion of the sebaceous glands or dead 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 are carriers of serious diseases: typhus, anthrax, encephalitis and trypanosomiasis.They cause enormous damage to human health, including death.
  2. Endoparasites (protozoa).
    Mainly affects internal organs.They are unicellular in structure, hence the name protozoa.Despite this, they can lead to severe forms of illness.The main diseases of this group are parasitic blood infection caused by toxoplasma and intestinal infections caused by amoeba or giardia.
  3. Helminths.
    They are the causative agents of the most common forms of parasitic infections.In the human body, their development cycles mainly take place in the intestines and tissues, where the manifestation of disease symptoms begins.

Roundworms (nematodes)

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

  1. Pinworm.The disease is caused by enterobiasis.It mainly affects children of preschool and primary school age.
  2. Whipworm.Causes the disease trichuriasis.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 is larger in diameter and contains the intestines.
  3. Ascaris.The disease is caused by ascariasis.Adults reach sizes of 25 cm (males) and 40 cm (females).After the larva enters the human body, it passes through the stomach and enters the small intestine.From there, through the pores with the blood flow, it enters the liver, then to the heart and then to the lungs, where it develops within 7-10 days.Then the larvae begin to rise to the larynx.Once they reach 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 grow to adults within 2-3 months.After this, reproduction begins and the cycle repeats.The female can lay more than 200 thousand eggs per day.
Roundworms

Tapeworms (cestodes)

These 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 in size (2-9 mm) and consists of several segments and suckers.The uterus of a sexually mature individual contains a large number of eggs, inside of which there are larvae.The main places of localization of echinococcus are the liver and lungs.There it causes a chronic disease called hydatid cyst.
  2. Bull tapeworm.Causes the disease teniarinchiasis.At the larval stage, it has an intermediate host - cattle.Once in the human body, it develops in the small intestine to the tape stage.The body of an adult parasite has up to 1000 segments, and it can reach 4-10 meters in length.
  3. Pork tapeworm.Causes the disease taeniasis.Externally, it is very similar to a bull tapeworm.It also has intermediate hosts: pigs, dogs, camels, hares and rabbits.In humans it is a parasite in the intestines.The size of an adult individual does not exceed 4 meters in length.
  4. The tapeworm is wide.The disease is caused by diphyllobothriasis.Lives in freshwater bodies of water.It uses crustaceans and fish as an intermediate host.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 from 300 to 3000 eggs per day.Further, with the blood flow, the eggs are spread throughout the body and continue their 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 especially dangerous.Also, a person becomes infected with a parasitic infection if the rules of personal hygiene are not followed.For example, not washing your hands before eating.
  2. Transplacental route.The parasitic infection is transmitted from a pregnant woman through the placenta to the child.For example, these are diseases such as toxoplasmosis, malaria or hookworm.
  3. Percutaneous path.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 that carry parasites.For example, malaria.

Symptoms

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

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

Diagnostics

Diagnostics

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

Diagnostic methods include:

  1. Stool examination.Allows you to determine the presence of most types of parasites that live in the intestines.Their eggs, larvae and body segments are excreted in 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 makes smears and examines them under a microscope.This method is often used, but it is not accurate enough.In order to make a final diagnosis, the patient must undergo this test up to three times with short time intervals.This is due to the life cycle of parasites and the laying of eggs, which are detected by this research method.
    2. Scraping (washing) from 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 in adults.For this reason, this analysis is carried out mainly for children.The laboratory technician moistens a cotton or glass eye swab in water or glycerin and rinses it from the perianal folds.Next, 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 assistant 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 viewed under a microscope.The parasite is diagnosed quite accurately.Using these methods, the laboratory assistant 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 patient survey to determine the presence of the parasite and determine its location.These biological fluids are analyzed using microscopy and macroscopy.First, the resulting sample is examined for the presence of adult individuals, and then microscopy is performed to detect eggs and larvae of parasites.
  3. Blood test.Modern methods of testing blood for parasitic infections make it possible to determine the presence and type of pathogen with high accuracy.Three types of such diagnostics are used:
    1. Serological reactions.Allows you to determine the presence of parasite antibodies in the patient’s blood serum.This method is considered highly specific, but inferior to PCR diagnostics.
    2. PCR diagnostics.This method is based on identifying the DNA of parasites in any biological fluid that was taken for analysis.
    3. Genetic research.It involves detecting the genome of the parasite in a patient's blood sample.This method is used much less frequently than all others, but has high accuracy.
  4. Examination of biopsy material and lymph nodes.For this analysis, the doctor excises a small section of an organ, tissue, or an entire lymph node and sends it for histological examination.This way the presence or absence of parasites is diagnosed.

Recommendations for preparing for testing

Before taking tests for parasitic infections, you need to properly prepare for them.If the recommendations are followed, the accuracy of diagnosis increases, since the material does not contain interfering factors that affect the effectiveness of research methods.

Preparing for a stool test:

  1. Antibiotics, anti-inflammatory drugs and antacids should be stopped.The use of medications and other drugs containing bismuth and iron is also unacceptable.
  2. If an X-ray examination using barium or a colonoscopy was carried out, during which an enema was performed to cleanse the intestines, then a stool test can be taken only after 2-3 days.
  3. It is not recommended to donate stool 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, do not eat fatty foods, and give up alcohol.
  3. A blood test for parasitic infections is taken on an empty stomach.Drinking a small amount of clean drinking water is allowed.

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

Treatment

Unfortunately, symptoms of parasitic infections cannot always be detected in the initial 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.

Therapy of infectious and parasitic infections is divided into two areas:

  1. Symptomatic treatment.Aimed at eliminating the clinical manifestations of the disease.These include lowering body temperature, getting rid of redness and itching, and normalizing the functioning of the gastrointestinal tract.
  2. Etiological treatment of parasitic infections is aimed at getting rid of the causative agent of the disease.

In some cases, surgery may be necessary.It is applicable for alveococcosis, echinococcosis and some types of trematode infection.

When the body is dehydrated, salt-containing solutions 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 food, after visiting the toilet, and coming home 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 may not always be free of parasites.Using home 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 need to 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.
  7. After visiting exotic countries, when working with land, as well as employees of children's institutions, it is recommended to be examined once a year for the presence of parasitic infections and, if necessary, carry out prophylaxis with medications.