The most common types of worms in humans

Various types of worms are found everywhere, with children making up 80% of those affected.Helminths or worms (from the Greek parasite worm) are lower worms that parasitize the body of humans and animals.They cause pathologies called helminthiasis.According to the WHO, every year 50% of the population is infected with: pinworms (1.2 billion people), hookworms (900 million) and whipworms (up to 700 million).

What kinds of worms are there?To date, more than 400 species of worms found in humans have been identified.All types of worms in humans are divided into 2 large groups: flat and round (nematodes).In turn, flatworms are divided into tapeworms (cestodes) and flukes (trematodes).Cestodes are also divided into tapeworms and tapeworms.

The opinion that worms in humans live only in the intestines is wrong;they can migrate with the blood stream throughout the body and settle in different places.All types of parasitic worms feed on their host and use it for their life cycle.

The circulation of worms in nature

To maintain their species, parasites must constantly move in the external environment, leaving their host and settling in the body of animals, using them as intermediate hosts.In this process, carriers are of great importance: mechanical - these can be insects that carry worms at a distance of their feet.Worms do not live in the body of insects.

Specific carrier or intermediate host - in which the parasites go through only one of their development cycles.In circulation, the method of transmission of the worms matters:

• contact - penetration through intact skin and mucous membranes (hookworm);
• nutritional.

Peculiarities of worm reproduction

For the most part, lower worms are hermaphrodites, but there are also worms with gender differences - nematodes.If helminths change several hosts during their development cycle (sometimes up to 4), they are called biohelminths.If they live with only one owner, they are geohelminths.

Developmental stages of worms:

1. Egg stages - the female lays immature eggs that mature in the external environment and are then returned to humans orally.
2. The second stage is when the egg hatches into a larva.This process occurs in the gastrointestinal tract.It migrates throughout the body, looking for an ideal habitat.Once it finds it, it continues to develop into an adult.
3. The third stage is the adult, which lays eggs again.It should be noted that worms do not develop in all organisms, but only in those that are suitable for themselves, i.e.for example, larvae whose host is an ungulate will survive if they enter the body of a predator, but will not lay eggs there.

Types of helminthiasis

Types of helminths in humans are divided according to their habitat: luminal and tissue.In the first case, the parasites live in the lumen of hollow organs, most often the intestines: ascariasis, trichuriasis, strongyloidosis, taeniarhynchiasis, etc.Tissues live in the thickness of various organs and tissues.What organs can be affected by worms?They can settle and affect the hepatobiliary system, brain, eyes, lymph nodes, lungs, so diseases can have several names:

• in case of liver damage - echinococcosis;
• brain damage - cysticercosis;
• lymph nodes - filariasis;
• pulmonary helminthiasis - paragonimosis;
• tissue helminthiasis - after the worms: trichinellosis, schistosomiasis, filariasis, toxocariasis.
• ophthalmic helminth infections - when parasites affect the eyes and more pronounced pathological changes are caused by the larvae and developmental stages of worms.

Habitat

Parasitic worms are found from the Arctic to the Equator, but those worms that are characteristic of the tropics will not be diagnosed in the inhabitants of northern latitudes.The degree of infection of the population with helminth infections depends on the economic level of the country and the climate.The most common types of worms are pinworms, roundworms and whipworms.The source of the infection becomes the organism - the ultimate host.

Ways of infection with worms:

1. The food route is eating unwashed or fly-infested food, insufficient heat treatment of meat, eating raw fish, drinking raw water, swallowing water while swimming in water bodies, using the same knife for raw and cooked food.
2. Fecal-oral transmission: contaminated household items, unwashed hands after using the toilet, contact with animals.
3. Path of transmission.Transmission through insect bites.

Infection from pets

In contact with a dog, you can become infected with tapeworms, echinococcus, roundworms and pig tapeworms.The eggs of the worms can be on the fur of the dogs, and in addition, these animals have a habit of eating other people's feces while walking.From cats: the same as in dogs, as well as cat fluke, from chicken - roundworms, from humans - pinworms, dwarf and pig tapeworm, hookworm.

How do worms affect the body?

Parasites sensitize the body with their waste products, toxins and enzymes, leading to:

• allergies and intoxication;
• mechanical damage to mucous membranes with suction cups and hooks;
• large worms can block the intestinal lumen.
• in addition, worms eat a significant part of the incoming BZHU, which causes anemia, deficiency of vitamins, trace elements, hypoxia, malnutrition;
• digestive disorders are noticed, children have a lag in psychophysical development.
• In many helminthiases, chronic microblood loss occurs.
• helminths worsen the course of existing pathologies, suppress the immune system, increase the risk of tuberculosis and cancer, and reduce the effectiveness of vaccinations.

Characteristics of the most common worms

What do roundworms look like?When cut, they have a round shape, which is why they got their name.Roundworms have their own characteristics.First of all, this is their extraordinary durability: they remain alive in formaldehyde for 5 years.In addition, they are distinguished by a simple development cycle, a digestive system in the form of a straight tube and rapid reproduction.

Horsetails cause enterobiosis (anthroponous disease, dirty hands disease).They look like small white worms up to 1 cm (males are only 3 mm), the end of the body is slightly pointed.They live in the lower parts of the small intestine and the beginning of the large intestine.They are contact worms.Egg laying takes place in the anus area.The development cycle lasts 2 weeks, they live 1-2 months.More often in children.They are attached to the intestinal wall with the help of head vesicles.Female sedges descend to the anus in the evening and lay eggs here.At the same time, they secrete a special kind of liquid that causes itching.The child scratches his bottom and self-infection occurs.After laying eggs, the females die.The damage they cause is the release of enzymes that irritate the intestinal walls and contribute to their inflammation.

Roundworms cause ascariasis.These are reddish-white roundworms up to 50 cm long and 6 cm wide.Males have a curved end.Roundworms live in the small intestine, but the larvae actively migrate in the body, their life cycle reaches one year.The larvae of the worms live in the lungs.Their waste products cause intoxication and intestinal obstruction.

Parasites are geohelminths, that is, they develop in the soil and from there reach humans.They are distinguished by enormous fecundity, up to 240 thousand eggs per day.The eggs have a very strong three-layered shell and fall easily into the soil.Here, under the influence of oxygen, humidity and a certain temperature, larvae are formed in them.This process can take from 2 weeks to several months, depending on the temperature.Such a mature egg with a larva re-enters the person orally.The larva emerges in the intestine and is carried throughout the body through the bloodstream.Its favorite habitat is the alveoli of the lungs because it has access to oxygen and the larva is aerobic.Adults are anaerobes.Reaching 3-4 mm in length, after 4-5 days the larva moves into the bronchi, which causes coughing.When coughed up, it is swallowed and returned to the intestines, where it develops to maturity.The life cycle of the parasite reaches one year.

Whipworm causes trichuriasis, belongs to the nematodes, has a color from grayish to reddish, reaches 2-5 cm, has a sharp hair like a head, which is why it got its name.The parasite adheres to the intestinal wall and feeds on the host's blood and mucosal tissues.Inhabits the large intestine and appendix, here the larvae reach sexual maturity and lay 3.5 thousand eggs per day.The life cycle of the parasite is 4-5 years.By damaging the intestinal wall, they contribute to its damage: causing appendicitis, diarrhea, abdominal pain, anemia.Helminth eggs fall into the soil with human feces, where they can persist for up to 2 years.

Toxocara causes toxocarosis.It is a yellowish worm that looks like a roundworm but is 15-20 cm long. It is a biohelminth;humans are infected by dogs.They live in the form of eggs.Larvae emerge from them in the human intestines.They migrate throughout the body, damage internal organs and cause allergies.The severity of the clinic depends on immunity and the number of helminths.Laying eggs per day - up to 250 thousand.Life cycle - up to 10 years.

Trichinella spiralis causes trichinosis, which is considered the most dangerous helminthiasis, as it often ends in death.The nematode is only 5 mm long.Infection occurs when eating poorly processed pork.The trichinella in the intestine is fertilized, the larvae become pregnant and hatch in the female.At one end, the female attaches to the intestinal wall and expels up to 2,000 live larvae.This process is called ovoviviparity and takes 3-4 days.Larvae are carried by the blood stream and settle in striated muscles, especially in the masseter, oculomotor, respiratory and shoulder flexors.The disease is severe: 2 weeks after the invasion, pain in the abdomen, muscles, head and joints, fever, swelling of the face, intoxication appear.In the muscles, after a month, the larvae are encapsulated in the form of a spiral and can remain in a cyst-like state for 20 years without losing their viability.After 1.5 months, recovery occurs with proper treatment.

Hookworm and nekator are similar to each other, so their helminthosis gets a common name - hookworm.They are up to 1.5 cm long and parasitize in the duodenum.Helminth is common but rarely detected.Larvae can penetrate the skin on contact with soil.The development cycle is very similar to roundworms.The hookworm lives in the intestines and feeds only on blood.A person can absorb 0.35 ml of blood per day.Therefore, anemia and dysproteinemia are a characteristic feature.

Flatworms have a flattened shape.There are no gender differences;they are hermaphrodites.They are attached to the intestines using hooks and suction cups.

The tapeworm is a tapeworm that causes taeniarhynchiasis.It has a small head with 4 suckers and 6 hooks and a ribbon body of 1000 segments reaching 20 m in length.The parasite is a biohelminth, the infection occurs through beef, where its larvae are located.Each segment contains hundreds of thousands of eggs.Without treatment, the tapeworm parasitizes people for up to 20 years.It lives in the small intestine, sucking nutrients over the entire surface of the body.Lives up to 10 years.

Pig tapeworm is a tapeworm that causes taeniasis or cysticercosis.it reaches 3-8 m and has a double crown of hooks.The life cycle is 20 to 30 years.It can live in any organ and is found in poorly cooked pork.The cycle is similar to the bull tapeworm.The segments of this tapeworm can crawl out of the anus, here on the surface of the skin they burst and the eggs come out.The helminth parasitizes the intestines, causing allergies and gastrointestinal problems.

Broad tapeworm causes diphyllobothriasis.The parasite is more than 10 m long, it is flat and wide.The biohelminth reaches humans through freshwater fish or crustaceans.For tens of years, the worms parasitize the small intestine, clinging to its wall.After 25 days, the parasites become adults.They feed on blood, causing diarrhea and abdominal pain.

Echinococcus is a biohelminth, a small tapeworm, up to 3-5 mm.On the head there are 2 wreaths of hooks and suckers;the parasite has 4-5 segments.The last is its reproductive system.It forms cysts up to 10 cm in the organs (Finns), where eggs and larvae are located.Cysts destroy the surrounding tissue.They can rupture, then develop toxic shock or multiple new cysts.The ultimate owner is the wolf, the intermediate owner is man.Infection through food or after contact with domestic animals.In the intestine, the larvae (oncospheres) emerge from the eggs and are carried throughout the body through the bloodstream.They settle, as a rule, in the parenchyma of the liver and lungs, but they also live in the intestines.Cysts can only be removed surgically.

A cat fluke is a liver fluke, cat fluke or Siberian fluke.Causes opisthorchosis.It is lanceolate in shape, 1-2 cm long and 2 mm wide, with 2 oral suckers on the head.Humans become infected through infected freshwater fish that have eaten a snail or crustacean with worm eggs.Humans are the primary host.The parasite lives in the lumen of the small intestine and bile ducts.The life cycle is up to 20 years;thousands of individuals parasitize a single organism at the same time.The acute phase of the disease is characterized by upper abdominal pain, fever, nausea, myalgia, diarrhea and rashes.When the process becomes chronic, symptoms of hepatocholecystitis are noticed, which do not disappear even after the worms are expelled.

Disease course and symptoms

During the acute phase, symptoms can appear at different times, depending on the incubation period, but most often begin after 2-3 weeks.The most common symptoms: allergic rash, lymphadenopathy, development of local or general edema, arthralgia and myalgia.If it migrates to the lungs, there may be coughing, attacks of suffocation, disturbances in stools (diarrhea), nausea and vomiting.

In the chronic phase, the symptoms depend on the organ in which the parasites have settled and their number.Key features include:

• frequent itching in the anal area;
• headache;
• vertigo;
• sleep disorders;
• flatulence;
• rash and itching;
• exhaustion with increased appetite;
• joint and muscle pain;
• yellowing of the skin;
• fatigue.
• prolonged low-grade fever may occur;
• discomfort in the navel area or in the right hypochondrium;
• periodic nausea and vomiting;
• bruxism;
• apathy.

The patient has pale, dry skin, loss of hair, eyebrows, eyelashes, brittle nails, tooth decay, bleeding gums, and bad breath.

Diagnostic measures and prevention

To make a diagnosis, a scraping is taken from the rectum and perianal area and a stool analysis is performed.In this case, the worms are very clearly visible under a microscope.A blood test for eosinophils and protein balance is taken.Sputum, gastric and duodenal contents can be examined.

Any helminths in humans are prevented by constant personal and public hygiene, sufficient heat treatment of meat and fish.Regular veterinary examinations and further treatment are required for all pets.