Echinococcus granulosa and Taenia solium

Echinococcus granulosa

Distribution

It is worldwide in distribution.

Habit and habitat

It is the digenetic parasite.

Primary host-Canine animal(Dog,Fox)

Secondary host-Man or domestic animals(sheep,pig goat etc)

The adult ofEchinococcusgranulosa are found in the intestine of canine host and the hydrated cyst is found in man or domestic animals.

Hydrated cyst

Larva stage is found inside the Hydrated cyst. It is the infective stage of the canine host of larval form inside hydrated cyst contains large number scolex in a invaginated form.

Morphology

It is a small tapeworm measuring 8 to 9 mm in length.The life span of adult worm in the canine host is 5 to 6 months but the larval worm may continue to develop for years.Body is divisible into three parts ie scolex, neck, and large proglottids

• Scolex: Scolex has four suckers and double rows of hooks.
• Neck: Neck is short and thick. It is the place where the stabilization takes place.
• Proglottids: It consists of three or four successive large proglottids.

First segment: It is slightly wider than the neck.It is the newly formed proglottids.

Second segment: It is mature segment it has well-developed genitalia. There is a large number of the testis and two distinct ovaries. Fertilization occurs in this segment.Third segment: It is much broader about 2 to 3 mm in length.It consists of a large number of eggs. The gray segments break off.

Egg: the egg is an infective stage in man and other domestic animals.It is oval in shape and contains hexacanth embryo with three pairs of hooklets.

Larva: Larva form is found within the hydrated cyst. It is the infective stage to dog larva form represents the scale of future adult worm which remains invaginated within a body.

Lifecycle

It is digenetic parasite primarily canine animal(Dog,fox)

Secondary host-man or domesticated animals

Infection to canine animals

Primary host is infected by ingesting the infected organs of domesticated animals containing innumerable scolices inside the hydrated cyst. On entering the primary host the scolex has four suckers and hooklets evaginated and developed into an adult .They may mature about 6 to 7 weeks and produce eggs and the eggs are discharged by the primary host along with faeces.

Infection to man or domesticated animals

The man is generally infected by handling the infected dog or by ingesting food containing egg of Echimoccus granulomas. The embryo hatches in the intestinal wall and reaches to the various part of the body through the blood stream. The embryo reach in the tissue they secrete a hyaline membrane and becomes surrounded by it. A hydrated cyst may contain thousands of scales called protoscolices.Protoscolices represent the scolex of potential adult bearing hooklets and suckers in a invaginated from this hydrated cyst when ingested by the dog are capable of growing adult worm.

Pathogenicity

It causes disease Echinococcosis. The mostly infected organ is the right lobe of liver and other organs are kidney, spleen, brain etc. Pain is the common symptoms.

Prophylaxis

1. The infected dog must be treated.
2. Avoid feeding infected organs of domesticated animals.
3. Periodic deworming of pet dog
4. Wash hand with antiseptic soap before eating.

Taenia solium

Distribution

It is worldwide in distribution. It is common in those people who eats insufficiently cooked pork meat.

Habit and habitat

It is a digenetic parasite.It completes is lifecycle in man and pig host.In man it is found in the small intestine and in pig host it is found in thick muscles of the pig. The life span of tapeworm is about 25 years.

Morphology

The adult tapeworm is about 2 to 3 meters in length.The body is divided into three parts ie. Scolex, neck, proglottids

Scolex: Scolex is pin size around 1 mm in diameter.It consists of crown shape rostellum double join of hooks and four suckers.

Neck: Neck is short unsegmented about 5 to 10 mm in length.

• Proglottids: Tapeworm consists of 800 to 900 proglottids.The proglottids contain reproductive organs like testis and ovaries. Proglottids are of three types depending on the maturity of reproductive organs
• Immature proglottids: Reproductive organs are not matured.
• Mature proglottids: Reproductive organs are matured and fertilization occurs.
• Gravid proglottids: It contains a large number of egg,this proglottid can disintegrate.

Egg: The egg is spherical and brown in colour.Egg contains a sphere with 3 pairs of hook let. It is an infective stage to the pig.

Lifecycle

Taenia sodium is a digenetic parasite

Primary host-man

Secondary host-pig

Life cycle of Taenia solium in human host

Human is infected by ingesting of raw or insufficiently cooked pork containing cysticercus cellulose larva inside the alimentary canal of man. The scolex is contacted with bite evaginate and develops into an adult worm by grandmas stabilization than the tapeworm start producing egg and discharged outside along with faeces.

Life cycle of Taenia solium in pig host

The egg along with gravid segment are passed out with the human faeces on the ground while the pig swallowed eggs. Then that reach to the alimentary canal of the pig. The wall of the egg rupture and released in the stomach of the pig,the outer membrane of the atmosphere is dissolved in acidic medium and liberated embryo which contains six hooks. These hooks penetrate the wall of the small intestine of pig reach to the circulation through the circulation. They attack the liver heart and finally settle down in the muscles.

Cestodiasis: It is the disease in man caused by infection due to the tapeworm. Human being get infected due to eating raw meat of pork containing cysticercus of tapeworm. A man may fall victim of an adult tapeworm as well as its cysticerci.

Treatment

Antihelminthic drugs like camo quite,carbon tetrachloride, antiphon,dichlorophene are common. The most satisfactory compound is yo mean. Under the action of drugs, the strobila is removed but the embedded scolex persists which again bud off so removal of scolex can be brought about by surgery.

Prophylaxis

1. Man should avoid inadequately cooked measly pork
2. The man who is injected should be charged their faeces in the safe place away from the pig.
3. Proper sanitation should be provided.

References

Arvind, Keshari K. and Kamal K Adhikari. A Textbook of Biology. Vidyarthi Pustak Bhander.

Michael J.Pleczar JR, Chan E.C.S. and Noel R. Krieg. Microbiology. Tata Mc GrawHill, 1993.

Powar. and Daginawala. General Microbiology.

Rangaswami and Bagyaraj D.J. Agricultural Microbiology.