parasite

-
• Objectives:
• to study the general characteristics of medically
• important tapeworms including their morphology,
• life cycle,habitat,nutrition, pathogenesis and
• laboratory diagnosis.

They have ribbon- like shape, flattened dorsoventrally & segmented .

All tapeworms have indirect life cycle except Hymenolepis nana.

Adult tapeworm inhabits the small intestine of vertebrates. While the larvae inhabit the tissues of vertebrates & invertebrates.

All tapeworms are hermaphrodites,

They have no gut or digestive tract,absorption of nutrient materials takes place through tegument (body wall).
.
Adult tapeworms produce minimal intestinal irritation and few systemic effects(mechanical and chemical effects).
Cestodes ( tape worms)


General characters

Morphology of adult tapeworms ;

Adult tapeworm divided in to ;
-Scolex or head provided with attachment organs .

-Neck or region of growth .

-Strobila or chain of segments or proglottids ;

1-Immature proglottids .

2-Mature proglottids.

3-Gravid proglottids.

Types of cestodes larvae;
A - Bladder larvae :

1-Cysticercus : e.g. T. solium, T. saginata.

2-Cysticercoid: e.g. Hymenolepis spp.

3-Hydatid cyst : e.g. Echinococcus spp.

4-Coenurus: e.g. Taenia multiceps.
B – Solid larvae:
1-Procercoid: e.g. D. latum.
2-Plercercoid (sparganum): e.g. D. latum.

Taenia saginata(beef tape worm)

-Disease ; Taeniasis
Beef tapeworm infection
-Habitat ;Upper part of
small intestine –
Proglottides;1000-2000
Length;4-10 m
Morphology;
-Morphology
1-Scolex (unarmed)
2-Neck

3- Strobila;

-Immature
Mature
Gravid
Gravid segment ;15 – 30 lateral uterine branches

Bladder larvae :

Cysticercus bovis : a true

bladder worm, It is oval in

shape, has fluid- filled

membranous bladder with

invaginated unarmed scolex.



Egg of Taenia spp.(S. S. C. C.)size;36 micron,shape; globular or spherical,color; yellowish browncontents; Taenia spp. eggs contain an embryo that is called an oncosphere or hexacanth embryo ,surrounded by thick,
radially striated embryophore. The egg surrounded by delicate egg shell.

- Pathogenesis, pathology & symptomatology

-Intestinal disturbance

-Acute intestinal obstruction

-Appendicitis


-Hunger pain

-Systemic intoxication

-Mental worried and embarrassment

Diagnosis

1-General stool examination ( egg and gravid segment )
2-Perianal swab (Scotch tape slide technique)
3-Examination of scolex (after medication)

Treatment

Niclosamide, praziquantel and mebendazole.

Taenia solium ( pork tapeworm )

• Taenia solium (pork tape worm)

• Disease: Taeniasis or pork tape worm infection.
• Habitat: upper part of
• Small intestine of man.
Adult:
• Length: 2-8 m
• Scolex: armed scolex
• Strobila; 800-1000

7 – 13 lateral branches

Larva: Cysticercus cellulosae

Membranous bladder with

Invaginated armed scolex

Cysticercosis : human tissue infection with

cysticercus cellulosae
• Hetero – infection.
• Auto – infection:
• External auto-infection.
• Internal auto-infection.


Pathogenesis ,pathology and symptomatology;

Adult worm:

• Intestinal obstruction
• Appendicitis
• Abdominal pain and discomfort
• Peritonitis in rare cases
.


•Clinical manifestations depend on size of the larvae and type of tissue invaded,mainly it takes place in subcutaneous tissues, skeletal muscles, brain and eye.
Larval stage:
• Severity of cysticercosis depend on :
Location, Size, Number of larvae and host immune response

Diagnosis

Adult:
• Egg in stool sample(microscopic exam.)
• Gravid segment(macroscopic exam.)
• Scolex


Larvae:
• Histopathological exam. of biopsy materials.
• Serology
• Radiology, CT scan & MRI.

Taenia multiceps (gid worm)

Adult worm , from 40 – 60 cm in length , the scolex with

double circle of hooks, it is found in the small intestine

of dogs , wolves and foxes .

Larval stage is called Coenurus cerebralis is found in CNS

of herbivores mammals ( sheep , goat and cattle)

, man infected accidentally.

larval stage produce a disease known as cerebral and ocular coenurosis .

Coenurus larva

Of T.multiceps