How Are Flatworms Different From Roundworms?

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How Are Flatworms Different From Roundworms?
How Are Flatworms Different From Roundworms?
Video: How Are Flatworms Different From Roundworms?
Video: Roundworms and Flatworms 2023, February

The morphology of round and flat parasitic worms - the difference between species


  • 1 Morphological features of roundworms
  • 2 Common types of roundworms

    • 2.1 Pinworms
    • 2.2 Ascaris
    • 2.3 Vlasoglav
  • 3 Morphological features of flatworms (trematodes and cestodes)
  • 4 Representatives

    • 4.1 Hepatic fluke
    • 4.2 Bull tapeworm

A person is susceptible to infection by parasitic organisms. Among these are flat and round worms. Parasites can live in the body alone or in whole colony. The lifestyle of an invasive agent directly affects the degree of harm done to a person.

Worms are dangerous for humans for three reasons: they emit toxins into the body, produced in the course of life; eat body tissues; large individuals are capable of displacing or displacing internal organs. The harm is multiplied many times over when the parasites begin to reproduce.


The human body can become an incubator for two types of helminths - flat and round. This text contains a basic analysis of representatives of both types of pathogenic organisms and conclusions that explain how roundworms differ from flatworms.

Morphological features of roundworms

Another name for the described type of parasites is "nematodes". To date, biologists have registered about 80,000 species of worms. Most representatives of the species lead a parasitic lifestyle, inhabiting the organisms of people, fish, wild and domestic animals, birds.

The main morphological feature of this type of helminth is the presence of a primitive digestive tract, which begins with cuticle teeth in the mouth and ends with the anus. The intestine is a straight tube of muscle tissue.

In the host's body, the roundworms feed on organic degradation particles and host tissues. Food processing products are thrown out through the aforementioned anus and a special gland located in the cervical region.

Parasites from the genus of nematodes are clearly differentiated by sex: males have a curved tubular proboscis intended for "conception". Nematode larvae go through five stages of maturation, each requiring a new host.

Common types of roundworms

Several dozen species of the described type of helminths are able to settle in the human body. Some species live alone in the host's body, but the overwhelming majority arrange giant colonies in the body, numbering several hundred thousand "tails": what is the difference between roundworms and flat worms: the latter prefer to "eat" the host without partners.

Let us briefly describe the types of helminths that a person can pick up in everyday activities with the greatest probability.



These small parasites have visited the organisms of the vast majority of earthlings. Pinworm eggs "wait" for the host in the soil or animal feces. You can swallow a pinworm egg if you eat an unwashed vegetable / fruit, drink unfiltered tap water.

The length of an adult female does not exceed 1 cm. Males, as a rule, are twice as short. The parasite lives in the small intestine, but lays eggs in the folds of the anus.

The described parasites are active at night (when the body is at rest): hence the unbearable anal itching during sleep. When a person sleeps, females actively lay eggs. For one clutch, the pinworm produces more than ten thousand eggs, which "ripen" in a few hours.

The infected person begins to scratch the painfully itchy anus and grabs a large part of the clutch under the nails, thereby helping the worms to spread. The pinworm lives no more than two months. To get rid of worms, a course of anthelmintic drugs is prescribed.



They are found in humans much less frequently than pinworms, nevertheless, being a common parasite. The described roundworm is much larger than the pinworm. The length of the female is up to half a meter; males are smaller - up to 20 centimeters.

A person is a favorite carrier for roundworm. In the environment, eggs "ripen" at high humidity and temperatures of 20-25єС. Eggs are ingested orally from the surface of dirty fruits and vegetables.

Roundworms "colonize" the host organism, laying hundreds of thousands of eggs per day. Ascaris is dangerous because it is a kind of “nomad”. In the process of life, it visits the lungs, heart, liver, while producing toxins. Ascaris intoxication can be determined by general lethargy, memory impairment.

Ascaris migration causes discomfort in the infected person and the desire to cough. Sometimes a person is lucky and he spits out a worm with phlegm.


The parasite is unique in that it feeds exclusively on human blood. The size is small - up to 0.5 cm. The female whipworm is capable of laying in the intestines up to 20,000 eggs per day. Eggs come out with feces and ripen in the soil. The adult attaches to the intestinal wall and drinks blood. At the site of the bite, tiny ulcers form, disrupting the functional state of the intestine.

Violation of the gastrointestinal tract, caused by the presence of a whipworm in the intestine, is called "trichocephalosis". When the disease is localized, a person feels anemia of the skin, a decrease in appetite. Neglected cases end with rectal prolapse.


Morphological features of flatworms (trematodes and cestodes)

The difference between flat worms and round worms is the presence of a pronounced head that performs the main nervous and reproductive functions. Flat worms are much larger than flat parasites: flukes and tapeworms can grow up to several meters. The body consists of several similar segments.

There is a wild tradition of European fashionistas of the past who want to lose weight. One segment of the bovine tapeworm was swallowed by the human. The segment grew to an adult, which provoked weight loss, dystrophy and many degenerative changes in the body.

Flat helminths parasitize in the host's body alone: ​​they do not need a partner of the opposite sex for reproduction, they are hermaphrodites. The sense organs in flatworms are absent. The pharynx is surrounded by nerve tissue that allows the worm's digestion to function. The parasite also lacks tooth buds. Trematodes and cestodes, unlike round helminths, do not have an anus.


For feeding flukes or tapeworms use suckers, which are attached to the walls of organs. The differences between flatworms and roundworms are not limited to the structure of the reproductive system or size: flatworms are able to survive in the aquatic environment.


Let's briefly describe the types of flat helminths dangerous to humans.

Hepatic fluke

The hepatic fluke does not often select a human as its host. The worm prefers cows, goats, sheep, camels. The creature has a wide body resembling a tree leaf (up to 5 cm long). There is a sucker on the belly of the helminth, with which it attaches to the hepatic wall and feeds. After laying eggs, the parasite leaves the host during bowel movements. Eggs can only develop in the aquatic environment. The larva can swim freely and search for a new host.

Having settled in a person, the fluke causes painful sensations. There is a general deterioration in health and liver failure.

Bovine tapeworm

Most dangerous if it enters the human body. The gluttonous white worm can grow up to 10 meters in a person

A person becomes infected with tapeworms by contact with livestock or by eating insufficiently thermally processed meat. The worm can live in humans for more than 10 years, permanently poisoning the body, laying eggs and even migrating.

Worms are most dangerous when they get to the brain or heart. The bovine tapeworm feeds, attaching itself to the intestinal wall with a sucker.

Bovine tapeworm infection is expressed in the following symptomatic series:

  1. A feeling of tightness in the abdomen;
  2. General decrease in tone;
  3. Inflammation of internal organs due to the pathogenic influence of parasites.

Chains do tremendous harm, feeding on mucosal particles and blood.


The differences between round worms and flat worms are obvious: flat parasites are much larger, more voracious and tenacious. They live in the host for years. At the same time, roundworms are no less dangerous: they are very prolific and numerous, capable of migrating throughout the body, affecting entire systems of internal organs.

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