Taenia solium




Дата канвертавання27.04.2016
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Taenia solium

Adult worms live in human small intestine causing taeniasis. The larval stage (Cysticercus cellulose) lives in pig or human tissues causing human cysticercosis.

I. morphology


  1. Adult is flattened ribbon-like, cream color, measures about 2-4 m and has 700-1000 proglottides. The head is global, about 1mm in diameter and equipped with 4 suckers and rostellum with 25-50 hooklets arranged in a double crown. The short and slender neck is the budding zone containing germinative cells from which new segments grow up to form a long and segmented strobilus. Immature proglottides are transverse rectangle, located in the anterior part of the body and inner organs are developing. Mature proglottides are square in shape and located in the mid part of the body and have 150-200 testes, a centrally straight uterus, 3 lobes of ovary and a vitelline gland. The pregnant proglottides are longitudinal rectangle, located in the posterior part of the body and contain a branched uterus filled with eggs. The number of main branches on each side of the uterus stem is 7-13.

  2. Egg, spherical in ship, 31-43µm in diameter, has a brown radially striated embryophore surrounding an onchosphere with 6 hooklets..

  3. Cysticercus cellulose. It is a semitransparent and elliptic bladder, about 0.6-1 cm. There is fluid and a white scolex with 4 suckers and kooklets in the bladder.

II. Life cycle

  1. final host: man,

  2. Intermediate host: pig (or man),

  3. Infective stage: cysticercus and egg,

  4. Infective mode: eating raw bean-pork,

  5. Site of inhabitation: adult in small intestine; cysticercus in tissues,

  6. Infective mode of cysticercosis: endogenous, exogenous auto-infection and foreign source;

  7. Life span: more than 25 years; cysticercus can survives 5-6 years in human body.

III. Diagnosis

  1. Taeniasis: Confirmative diagnosis of taeniasis is made by finding gravid proglottids or egg in stool. (1) direct fecal smear (2) brine floatation technique **(3) cellaphane-tape technique

  2. Cysticercosis: Biopsy of subcutaneous nodules, X-ray ,CT 0r MR are used for the diagnosis of brain type and ophthalmoscope examination is used for ocular form.

  3. Immunological tests are for reference only.

  1. Intradermal test.

  2. Indirect hemagglutination

  3. Enzyme-linked immunosorbent assay( ELISA)

IV.Requirements

1.Study the morphological characters of ova and adult worms of T. solium

2.Realize the life cycle of the worm.

3.Master the methods of the diagnosis.

V. Individual observation

The eggs and scolex, gravid segment of T. solium

VI.work

Draw an egg of T. solium




Taenia saginata


Adult worms live in human small intestine causing taeniasis. Larval stage (Cysticercus bovis) lives in cattle tissues. This disease is prevalent all over the world.

I. Morphology:

1. The biological differences between T. solium and T. saginata

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Adult T. solium T. saginata

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length 2-4 meters 4-8 meters

scolex 1mm in diameter with 2mm in diameter, with

4 suckers and hooklets 4 suckers but no hooklets

Number of 700 to 1000 1000 to 2000

Proglottids

Mature proglottid 3 lobes of ovary 2 lobes of ovary

Gravid proglottid 7-13 uterine lateral 15-30 uterine lateral

branches on one side branches on one sideNumber of gravid usually several usually single segment

proglottid detached segments

Mode of proglottids passively expelled actively migrate out of

passing out anus

Cysticercus scolex with hooklets no hooklets on scolex

found in man and pig only found in cattle

Disease caused taeniasis and cysticercosis taeniasis

in man

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2. Egg: same as that of T solium

II. Life cycle:

Interrmediate host is cattle and cysticercus bovis can not live in human. The others same as those of T. solium.

III. Diagnosis:

Finding of gravid proglottids or eggs at the perianal region by cellophane tape method.

IV.Requirements

1.Study the morphological characters of ova and adult worms of T. saginata

2.Realize the life cycle of the worm.

3.Master the methods of the diagnosis.

V. Individual observation

The eggs and the scolex, gravid segment of T. saginata

VI.work


Draw an egg ofT. saginata
Echinococcus granulosus

Adult worms live in the small intestine of canine animals. It is metacestode (larval stage) live in the tissues of herbivores or men, which causes echinococcosis (hydatid disease or hydatidosis). This disease is prevalent in pastoral areas.

I. morphology


  1. Adult: It is the smallest tapeworm of medical importance, 2-7mm. It consists of a scolex, neck and three segments. The globular scolex, 0.3 mm in diameter bears a rostellum with a double crown of 28-48 large and small hooklets and 4 suckers. Behind the neck first proglottid is immature. The middle proglottid is mature with developed reproductive organs. The last or gravid proglottid has a median uterus with from 12 to 15 or more lateral branches filled with eggs..

  2. Egg, Same as the egg of Taenia solium

  3. Hydatid cyst is spherical, from 1cm to 20 cm in human body. It consists of a cyst wall (external cuticle layer 1mm and internal germinal layer 20µm), cyst fluid, brood capsules containing protoscolexes, daughter cyst and grand daughter cyst whose structures are same as that of the mother cyst. The formed materials found in the mother cyst are known as “hydatid sand”. The hydatid fluid has antigenicity and causes allergic reactions.

II. Life cycle

1. definitive hosts are dogs and wolves(canine), 2. Intermediate hosts: herbivores ( sheep, goat, camel, horse) and man. 3. Infective stage: egg 4. Infective route: ingesting eggs, 5. Hydatid cyst survives 40 years.

III. Diagnosis

Presumptive diagnosis may be made by patient’s history of living in pastoral areas, symptoms and signs. The clinical diagnosis depends on the detection the indicatives of hydatid cysts. The hydatid thrill, indicative of fluid, is a diagnostic sign. The exploratory puncture for obtaining fluid is contraindicated as a dangerous diagnostic procedure.



  1. B ultrasonography

  2. Computerized tomograph ( CT ) and MR.

  3. X-ray for cysts in the lung and bone.

  4. Immunological tests are for reference only:

  1. Casoni’s intradermal test.

  2. Indirect hemagglutination

  3. Enzyme-linked immunosorbent assay( ELISA)

IV.Requirements

1.Study the morphological characters of hydatid cyst

2.Realize the life cycle of the worm.

3.Master the methods of the diagnosis.



V.Individual observation

Hyditid sand


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