9+ Examples Of Endoparasites: Detailed Facts


In this post, you will find the examples of endoparasites, their classification and detailed characteristics.

Endoparasites are parasites that stay inside the host’s body living as intracellular or intercellular and derive nutrition from the host. They are permanent parasites.

Examples of Endoparasites are :

Fasciola

It is a leaf-like structure having 2-5cm in length. It is soft and pinkish-brown with a black lining in color. The body contain different parts for attachment, ingestion and egestion. 

The mouth takes part in ingestion as well as egestion. The Acetabulum is present for attachment of the body to the host. Genital pore is present between two suckers. The body contains the cuticle with tiny spines. These endoparasites are digenetic in nature means having two host. Excretory organ is flame cells which excrete ammonia and fatty acids.

Examples of endoparasites : Fasciola hepatica. Fasciola gigantica

examples of endoparasites
Examples of endoparasites : Fasciola hepatica from wikipedia

Taenia

It has elongated tape or ribbon-like appearance having 2-12m in length which varies among different species. Body is divided into neck, head and strobila. Body color is creamy yellow or greyish. Strobila constitutes the main body. 

It contains 800-1000 of segments which are called proglottides. Only neck portion is unsegmented which helps in producing new proglottides and this phenomenon is called strobilisation. It is also digentic in nature, man is primary host while pig is secondary host in T.solium

Examples of endoparasites : Taenia solium and T.saginata

Examples of Endoparasites: Life cycle of Taenia solium from Wikipedia

Echinococcus

It is 3-6mm in length. Body is divided into scolex, neck and strobila. Scolex contain four suckers, neck is short and strobila have only three proglottides. Adult worm generally reside in small intestine i.e., duodenum and jejunum of dogs while larval stage is found in humans. It completes its life cycle by using two hosts: Dog and Fox is definitive host while sheep is intermediate and man is accidental intermediate host. 

Intermediate host ingests the eggs of echinococcus, hexacynth embryos are released that penetrate the intestinal wall and reached the liver, further developed into hydatid cyst, some embryos passed from liver and get caught in pulmonary capillaries. After this, if carcasses of sheep are ingested by dog, it will grow in intestine and develops into adult worm and further eggs are released into feces and cycle continues.

Examples of endoparasites : Echinococcus granulosus

Examples of endoparasites: Echinococcus granulosus from Wikipedia

Ascaris

It is elongated and cylindrical in morphology with variation in size as sexes are separate. The male is short and narrow having 15-30cm in length while female is broader and longer having 20-40cm in length. 

Color is pinkish to white with pointed ends and four streaks – one dorsal, one ventral and two lateral. It is monogenetic in nature means having only one host. Common intestinal endoparasite generally found in the small intestine of human beings. It is more common in children.

Life cycle of Ascaris lumbricoides from Wikipedia

Posterior  end is curved in male. Cloaca is present in male at posterior end having two penial spicules. Gonophore and a separate anus is present in female.

Example: Ascaris lumbricoides

Ancylostoma

It is commonly called hookwarm endoparasite found in human small intestine. Its appearance is small and cylindrical having size of 8-13mm long. Sexes are separate, female is quite long in comparison to male.

Ancylostoma duodenale from Wikipedia

The anterior portion has a buccal capsule that contains a mouth with two chitinous cutting plates. These cutting plates posses teeth which helps the organism to tear the intestinal mucosa. They basically sucks 0.8ml of blood per day which results in a condition called anemia.

Example: Ancylostoma duodenale

Enterobius

It is also called pinwarm, seatwarm or threadwarm. It is small and round in appearance having size of 3-13mm and monogenetic in nature, males are comparatively shorter than females. This parasite generally inhabits the colon and other parts of the large intestine in children and women.

Life cycle of Enterobius Vermicularis from Wikipedia

The anterior portion of mouth has a pair of cuticular expansion called cephalic alae. The posterior end is curved in males having a penial spicule and pair of cuticular expansion called caudal alae. It causes enterobiasis or oxyuriasis.

Example: Enterobius vermicularis

Wuchereria

It is cylindrical and thread like in appearance having size of 4-8cm. They were commonly known as filarial worm. As the sexes are separate, males are shorter than females. Digenetic in nature, primary host are humans and secondary host is female mosquito of Culex.

Cycle starts when male and female bug copulate in lymphatic gland. It gives birth to juveniles called microfilariae. These microfilariae pass on to blood vessels of skin during night. Female culex picks up the microfilariae from the skin where juveniles grow and become mature to affect the new human host.

Life cycle of Wuchereria bancrofti from Wikipedia

Their growth in human host causes blockage of lymph vessels and causes a condition called lymphodema. The tissue around the blocked lymph grows and become harder. As a result that area becomes enlarged and huge, it is also called elephantiasis. Common organs which are affected : breast, leg and foot.

Examples of endoparasites: Wuchereria bancrofti

Trichuris

It is also called whip bug generally inhabits the large intestine of humans. Males are shorter having length of 30-40mm while females are quite longer with size 40-50mm. Anterior end in males is very thin while posterior end is coiled. Monogenetic in nature i.e.,man is the only host. 

Embryonated eggs (which have larva inside them) are ingested by human, these embryonated eggs are reached to small intestine where they hatches. Adult male and female are formed in the cecum and  inhabits the large intestine once they hatched.

Trichuriasis from Wikipedia

The fertilisation occurs and forms unembryonated eggs which further passes to the stools once they are completely divide to form embryonated eggs which is again ingested by humans through contaminated food or water.

Example: Trichuris trichuiria

Trichinella

It belongs to the class Nematoda, commonly called trichina bug. Found in Europe, USA, Africa except India. They generally resides in duodenal and jejunal mucosa i.e., small intestine. Males are shorter than females. Larva of adult worms are encysted in straited muscles of deltoid, diaphragm and biceps.

Trichinella spiralis life cycle from Wikipedia

Life span of these organisms is very short, males dies after fertilisation while female dies after releasing larvae. Monogenetic in nature but require another host to complete the cycle. Humans ingest pork flesh, digestive enzymes release the larval form in stomach.

Differentiated into male and female worms, produces larva into small intestine, larva moves to straited muscle and become encysted as man is the last host, while if it encysted in rat, it can transfer to the another host like pork or other rat to complete their cycle.

Example: Trichinella spiralis

Dracunculus

It is also called Guinea bug. Digenetic in nature i.e., definitive host is man while intermediate host is copepods or cyclops. One can affected by this organism by drinking contaminated water having cyclops with L3 larvae. 

Life cycle of Dracunculus medinensis from Wikipedia

Larvae are released in the body when copepods dies. They penetrate the stomach and intestinal wall of the host wher they and reproduce to form new L1 larvae.

Fertilized female bug moves to the skin and causes blister to release larvae. These L1 larvae are released into water body by affected host. Copepods consume the L1 larvae where they molt and forms type L3 larvae and continue the cycle.

Example: Dracunculus medinensis

Saif Ali

Hi, I am Saif Ali. I obtained my Master's degree in Microbiology and have one year of research experience in water microbiology from  National Institute of Hydrology, Roorkee. Antibiotic resistant microorganisms and soil bacteria, particularly PGPR, are my areas of interest and expertise. Currently, I'm focused on developing antibiotic alternatives. I'm always trying to discover new things from my surroundings.  My goal is to provide readers with easy-to-understand microbiology articles. If you have a bug, treat it with caution and avoid using antibiotics to combat SUPERBUGS. Let's connect via LinkedIn.

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