Lancet Fluke - The Structure And Life Cycle Of The Fluke

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Lancet Fluke - The Structure And Life Cycle Of The Fluke
Lancet Fluke - The Structure And Life Cycle Of The Fluke

Video: Lancet Fluke - The Structure And Life Cycle Of The Fluke

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Last updated 22 June 2017 at 02:04 PM

Reading time: 3 minutes

To date, science knows about the existence of more than 7000 species of flatworms leading a parasitic lifestyle. The lanceolate fluke or fluke of the lanceolate class is one of them.

They usually feed on substances produced by the body of ruminants, but they can parasitize in the gallbladder or intestines of humans and other mammals.


  • 1 Building
  • 2 Stages of maturation and reproduction
  • 3 Life expectancy

    3.1 Similar articles


The lanceolate fluke has a relatively small size, the length of an adult usually does not exceed 10 mm, and the width is 3 mm. dimensions are relatively small - body length is not more than 10 mm.

The worm got its name from its external resemblance to the lancet. Marita (Sexually mature parasite) has two suckers, one is not large for the mouth and a large abdominal one.

Internal organs consist of:

  • the digestive system, which includes the pharynx, esophagus, intestines and mouth opening through which the remnants of nutrients are removed;
  • simple nervous and excretory system;
  • the reproductive system, consists of the testes, one small ovary, ootype, oviduct and uterus, which occupies most of the parasite's body.

The structure of fluke eggs also has characteristic features. At one end of the oval helminth egg, a cap is provided for the larvae to emerge.

Maturation and reproduction stages


The life cycle of the lanceolate fluke is very complex and is carried out only when 2-3 carriers change.

For convenience, it can be divided into 4 important stages:

  1. eggs or larvae of helminths infect a land mollusk. In the body of the first carrier, two generations of larvae of the second stage of development (sporocysts) are formed, which in turn reproduce daughter larvae. They give birth to free-swimming caecari with a tail for swimming;
  2. after 3 months, the cecarii, together with the mucus secreted by snails through the respiratory openings, enter the external environment, where they are eaten by brown forest, meadow or red-cheeked ants from the genus Formika. In the body of the second additional host, the larvae turn into adults, ready to parasitize the body of the main host. Several parasites form a cyst in the nervous system, as a result of which the ant cannot descend and remains on the grass due to paralysis of the jaws;
  3. then the life cycle continues in the body of the next main carrier, where they reach puberty;
  4. lanceolate fluke is hermaphrodite and reproduces only in the body of the main carrier. The seminal fluid of the adult helminth Marita through special channels enters the cirrus, and then into the Ootype where the seminal and uterine canals lead and fertilization takes place. The formed eggs of the lanceolate fluke, ripening in the uterine cavity, enter the host organism through the uterine opening. As a result of defecation, eggs ready for infection with the host's waste products enter the soil, where they are swallowed by the mollusk.

The fluke of the genus lanceolate is widespread on all continents of our planet, the largest population of Helminth is recorded in the livestock countries of Eurasia, where worms infected cattle, goats, bananas, pigs and even rodents.

There have been cases when about 50,000 individuals of this worm were found in one sheep.

Life span

The life of a parasite consists of changing several hosts on which its duration directly depends. The first station of the cycle from the moment the mollusk swallows an egg until the larvae emerge can last about 5 months. In the body of the next host, the larva throws off its tail and can parasitize for more than 12 months, without killing the ant.

In the biliary tract of the final host, the lanceolate fluke reaches puberty and turns into Marita. This takes 1-1.5 months, and after 4 weeks the parasite begins to produce eggs.

At the moment, there is not enough information about the duration of the incubation period and the total life span of an adult fluke in the body of the last host.

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