CESTODES

Dr Mohiedden M Abdul-Fattah

• Final host:

• Intermediate host (IH):

• Paratenic IH

• Reservoir Host:

• Prepatent period

• Auto infection:

• Non-patent Infection

Life cycle in human trematodes

Cestodes LC

Adults in the intestines of:

Eggs in water or soil

Aduts in human intestine1. D latum 4. Hymenolepis nana

Larva in tissues of1. Salmon fish

(plerocercoid)4.Villi of Man intestine or

flea (cysticercoid)

Larvae in tissues of Man & others

2. T. saginata

3. T.solium

5. H. diminuta

6. Dipylidium

5.Beetles ( cysticercoid)

6.Dog flea (cysticercoid)

2. Cattle (C bovis)

3. Pig (C cellulosae)

1. Cyclops (procercoid) & frogs, Man ( Sparganum)

2. Sheep, rat and Man (hydatid cyst and Coenurus)

3. Man and pigs ( cysticercus cellulosae)

1. Cats and dogs (Diphyllobothrium mansoni)

2. Dogs, foxes and cats (Echinococcus & Multiceps)

3. Man only (Taenia solium)

2-Egg in soil

3-Larva in tissue of IH

Pseudophyllidea: Diphyllobothrium latum

2-Egg in soil

1-Adult in intestine of

Man

3- Larvae in tissue of intestinal villi of

Man

Cyclophyllidea:H. Nana Direct LC

1-Adult in intestine of man

2-Egg in

water

3- 1st Larva in cyclops

4- 2nd larva in fish

Intestinal cestodes

1-Adult in intestine of

ManCyclophyllidea: 1.Taenia saginata2.T. solium3.Hymenolepis

nana. 4.H. diminuta5.Dipylidium

caninum

Man is usually infected by intestinal cestodes when ingests the larvae except H.nana, infection occurs by eggs.

All Cyclophyllidea must need one intermediate host in their life cycle except H. nana

The IH in Taenia is vertebrate host (cattle or pigs). In Hymenolepis and Dipylidium it is invertebrate

insect (fleas, beetles or cockroach) Pseudophyllidea (D. latum) needs two

intermediate hosts in their life cycles: (Cyclops as 1st IH and Salmon fish as 2nd IH.

OUTLINE OF LLIFE CYCLE IN INTESTINAL CESTODES

• Tissue cestodes: all are larvae.

• The larvae are either

• Solid in pseudophyllidea as 1. sparganum of (Spirometra) mansonoides, or

• Cystic in cyclophyllidea as

2. Cysticecus cellulosae of T.solium,

3. Coenurus of T.multiceps, and

4. hydatid cyst of Echinocccus granulosus

5. Alveolar hydatid cyst of E.multilocularis.

Sparganum

1) Ingestion of egg or larva never gives adult in man2A) Ingestion of eggs never gives adult in man but ingestion of

larva can2B & 2C) ingestion of egg or larva never gives adult in man

Human tissue cestodiases

• Man is infected by larval tissue cestodes when he ingests the eggs

• The only exception is the infection by sparganum

• It is caused by ingestion of procecoid in cyclops or plerocercoid (sparganum) larvae in fish or frogs.

• The cyclophylidean larval cestodes are cystic in vertebrate intermediate hosts.

• Pseudophyllidean larval cetodes are worm like in invertebrate IH (Cyclops) and/or vertebrate host.

Tissue cestodiases1. Sparganosis : by sparganum; larva of

Spirometra.

2. Cysticercosis: by cysticercus cellulosae; larva of T. solium.

3. Cystic hydatidosis: by hydatid cyst; larva of Echinococcus granulosis.

4. Alveolar hydatidosis: by multilocular hydatid cyst; larva of E. multilocularis

5. Coenurosis: by Coenurus; larva of Multiceps multiceps

Final hosts

Adult worm Intermediate hosts

Larval stages

1st Larva 2nd Larva

Dogs, cats

Diphyllobothrium mansonoides

Man, frogs

mammals

Procercoid

(Cyclops)

Sparganum

Man Taenia solium Man, pig Cysticercus cellulosae

Dogs, wolves, foxes

Multiceps multiceps

Man, Rabbits sheep

Coenurus cyst

Dogs Echinococcus granulosus

Man, Sheep camels

Hydatid cyst

cats, foxes

Echinococcus multilocularis

Man, rodents

Alveolar hydatid cyst

Tissue cestodes: larvae, their adults and hosts

Mode of infection in tissue cestodiases• Pseudophyllidea:I. Sparganosis1. Ingestion of Water contaminated by Cyclops

containing procercoid larva.2. Ingestion of meat of IH infected with sparganum

larva.3. Skin or mucous membranes contact with meat of IH

infected with Sparganum larva• Cyclophyllidea:• Cysticercosis:• Ingestion of egg of T. solium in human's feces

contaminating vegetables or food:

Mode of infection in more Cyclophyllidean tissue cestodes

o Ingestion of Taenia like egg in feces of dogs contaminating vegetables or food:

2. Coenurosis: dog's feces: (eggs of Multiceps)

3. Cystic hydatidosis: dog's feces: (eggs of E. granulosus)

4. Alveleolar hydatidosis: dog or cat's feces: (Eggs of E. multilocularis)

Intestinal Cestodes: Pseudophyllideaworm Dipyllobothrium latum

Man Final host

Reservoir Fish eating animals: cats, dog, birds

Habitat Small intestine

Exit stage Egg: Immature, operculate, abopercular knob, yellowish brown, 75 X50 µm.Segments with rosette shaped uterus passed in chains.

Intermediate host

1st : cyclops in fresh water2nd : Salmon fish

Infective stage Plerocercoid in fish

Mode of infection

Ingestion of plerocercoid in salmon fish

Disease 1. Enteritis & abdominal colic 2. megaloblastic anemia due to vitmin B12 consumption

diagnosis 1. Detection of eggs or segments passed in chains in stool

Treatment Oral Praziquantel

Control 1. Thorough freezing or cooking of fish04/08/2317

Intestinal Cestodes: Cyclophyllideaworm Taenia saginata Tenia solium

Man Final host

Reservoir None

Habitat Small intestine

Exit stage Egg: mature, round, striated shell, yellow brown, 30-40 µmGravid Segments with branched uterus singly in saginata, in chains (solium)

I. host Cattle Pigs

Infective stage Cysticercus bovis in beef Cysticercus cellulosae in pork

Mode of infection

Ingestion of C. bovis in beef Ingestion of C. cellulosae in pork

Disease 1. Enteritis 2. obstruction 1. Enteritis 2. obstruction• Cysticercosis: by antiperistalsis or by

external autoinfection

diagnosis 1. Detection of eggs or segments passed in stool

Treatment Oral Praziquantel or by Albendazole

Control 1. Thorough freezing or cooking of pork and beef.2. Sanitary disposal of human sewage

04/08/2318

Intestinal Cestodes: Cyclophyllideaworm Hymenolepis nana H. diminuta Dipylidium

Man Final host Occasional f. host Occasional final host

Reservoir None rodents dogs

Habitat Small intestine

Exit stage Mature, Spheroid egg, thin shelled, 30-45 µm with polar filaments

Mature ovoid 70-80µm with polar knobs

egg capsules with cluster of eggs each 20-30 µm

Intermediate host

None or fleas Beetles or fleas Fleas, dog lice

Infective stage Egg, cysticercoid in fleas Cysticercoid insect Cysticercoid

Mode of infection

Ingestion of egg in food or cysticercoid in insect

Imgestion of cysticercoid in fleas

Ingestion of cysticercoid in flea

Disease 1. Enteritis 2.Insomnia Enteritis enteritis

diagnosis Detection of egg in stool Detection of egg in stool

Detection of eggs or segments in stool

Treatment Oral niclosamide or Praziquantel

Control Health education.Personal hygiene

Flea controlRat control

Avoid playing with & treta pet animals04/08/2319

Tissue (Larval) Cestodes (Tapeworms): PseudophyllideaAdult worm Diphyllobothrium mansonoides

Larva Sparganum

Man Paratenic Blind end Intermediate host

Reservoir Frogs, snakes, birds (paratenic hosts)

Habitat Skin, muscles, eye, brain

Exit stage None

final host Cats

Infective stage Procercoid in cyclops and sparganum in frogs

Mode of infection

1. Ingestion of infected cyclops 2. ingestion of infected frogs.3. The use of meat of infected frogs as poultice on skin lesions

Disease 1. Skin and muscle nodes 2. Eye: conjuctivitis 3.Brain: fits

Diagnosis Identify larva in excision biopsy

Treatment Surgical removal or ethanol injection

Control Adequately cook meat of paratenic hostsDo not use this raw meat as poultice

04/08/2320

Tissue (larval) Cestodes: CyclophyllideaAdult Taenia solium T. multiceps E. granulosus E. multilocularis

Larva Cysticercus cellulosae Coenurus Hydatid cyst Alveolar hydatid

Man Blind end intermediate host

Reservoir Pigs Sheep, rabbits Sheep, camels rodents

Habitat Eye, brain, skin, muscles Eye, brain Liver, lung, brain Liver, lung, brain

Exit stage None None None None

final host Man Dog, foxes dogs Wolves, foxes, cats

Inf. stage Taenia solium egg egg egg eggMode of infection

1.ingestion of egg in foods2.Internal auto infection 3.external auto-infection

Ingestion of egg in foods

Ingestion of egg in foods

Ingestion of egg in foods

Disease Blindness, fits, skin nodes Blindness, fits Jaundice, hemoptysis, fits

Jaundice, hemoptysis

Diagnosis 1. Imaging 2. biopsy 3. serology (Immunoblot)Treat. Albendazole, cortisone,

surgerysurgery Albendazole,

surgeryEarly surgery

Control 1 Treat intestinal taeniasis2 sanitary disposal of sewage 3 avoid emetics

1. Avoid playing with dogs2. Treat pet dogs

1. Avoid cats2. Early diagnosis

04/08/2321

  Spar-ganosis

Cysti-cercosis

Hyda-tidosis

Alveolar Hydatidosis

Coen-urosis

Final host Dogs, cats man dogs Dogs, cats dogs

Adult worm Spirometra T. solium E. granulosus

E. multilocularis

Multiceps

1st IH Cyclops Pigs

man

Sheep

man

Rodent

man

Sheep

man2nd IH

(paratenic)Frogs

(man)

nil nil nil nil

Inf. stage of man

Procercoid

sparganum

Taenia egg

Taenia like egg

Taenia like egg

Taenia like egg

Exit stage None None None None NoneDiagnosis Imaging, Biopsy, and sero-testing

Summary of Epidemio-Biologic Aspects of Tissue Cestodes

•Sparganosis• Definition: infection of human tissues with the

sparganum larvae of Spirometra mansonoides

I. Biology

I. BIOLOGY• Two species: 1. Spirometra. mansonoides2. S. proliferum (proliferative sparganosis); the larva

proliferate into surrounding tissue by lateral budding. • Man never acts as final host, but dogs and cats do.• Man acts only as dead end paratenic IH Host.• Habitat of larva in man: subcutaneous tissue,

muscles, eye and CNS.• Exit stage from man: none, but diagnosis made

when sparganum is surgically recovered.• Exit stage from dogs and cats: Immature eggs

passed in faeces (in water)

II. Epidemiology• Distribution: southeastern Asia and east Africa.• Transmission:• Intermediate hosts: • Cyclops is 1st IH and • Frogs, snakes, birds and mammals are 2nd IH.• Resevoirs: Birds and other mammals.• Infective stages: procercoid and sparganum.• Mode of infection:1. Ingestion of Cyclops containing procercoid of S.

mansonoides2. ingestion of sparganum in flesh of frogs, snakes or

birds.3. cutaneous exposure using the uncooked meat of these

infected animals as poultice on an inflamed skin or eye.

III. Host-parasite relationship• Pathogenesis:1. Depends on final location of migrating sparganum  2. Spargana may locate anywhere.3. subcutaneous tissue, breast, orbit, urinary tract,

pleural cavity, lungs, abdominal viscera and CNS• Clinical picture:  1. The migration in subcutaneous tissues is usually

painless, 2. but nodules on the chest and legs may be painful.3. in the brain: headache, fits may occur 4. In the orbit: conjunctivitis and periorbital oedema.5. In the inner ear: vertigo or deafness may occur. 

IV. Diagnosis:

1. Excision and identification of sparganum in the lesion. ~5 cm white glistening worm.

2. Imaging: CT or MRI

3. Serotesting for specific antibodies (ELISA)

ophtlamoscopy

V. Treatment1. Spargana are resistant to praziquantel

and mebendazole.

• Currently there is no recommended drug therapy for sparganosis. 

2. Surgical removal of the complete sparganum is the best treatment.

3. 40% ethanol injection with procaine to kill the larva in situ after which they are allowed to be absorbed.

VI. Control

• Avoid sources of infection:

1. Cyclops: Boiling or filtering of water in endemic areas.

2. Frogs and birds: Do not use their flesh as poultices.

3. Frogs and birds: Do not eat their undercooked meat.

CysticercosisInfection of human tissues by

cysticercus cellulosae; larva of Taenia solium.

I. Biology• Man act as final host and source of eggs. He

harbors the adult in his intestine.• Man act as dead end IH by harboring the larva

of T. solium (C. cellulosae) in his tissues.• Habitat of cystic larvae: 1. subcutaneous and intermuscular tissues, next

in the eye, then in the brain and other organs. 2. They are rare in spinal cord• Exit stage: none, but larva can be recovered

surgically

II. Epidemiology• Distribution: Mexico, south and central America,

Africa ,Asia.1. Intermediate host: pigs, monkeys, man.2. Reservoir hosts: the same animals.3. Infective stage: eggs or gravid segments of T. solium.4. Man is the only source of infection by cysticercosis5. Modes of infection:a. Ingestion of the eggs in contaminated food and drinks

(hetero-infection).b. Auto-infection of persons by faeco-oral transmission of

eggs from adult worms in their intestines.c. Internal autoinfection; eggs are carried by reversed

peristalsis back to the duodenum, hatch and induce cysticercosis.

III. Host parasite relationshipA.Pathogenesis• As the larva begin to die • a pronounced cellular reaction occurs,

followed by fibrosis, necrosis of the capsule and calcification of the larva in all tissues Except.

• In the eye, ventricles of the brain, and in the subarachnoid space.

• There is no fibrosis, but hydrocephalus occur• When cysts exist in vital organs; acute and

sometimes fatal sequences develop.• The location in the eye may be sub-choroidal,

sub-retinal, and intra-vitreous.

III. Host parasite relationshipB. Clinical picture:• Ocular cysticercosis: 1. visual impairment due to shadows cast by the

larva in front of retina.2. If not removed, it will produce uveitis, retinitis,

retinal detachment and blindness.• Cerebral cysticercosis:1. Adult onset epileptic fit.2. Obstructive hydrocephalus.3. Meningitis4. Behavioral disturbance.• Intermuscular nodules.• Subcutaneous nodules.

Subcutaneous nodules Intermuscular nodules

IV. Diagnosis• Detection of egg or gravid segment of Taenia

solium in stool may suggest auto-infection.• Imaging:1. Plain x-ray.2. CT and MRI: most effective in cerebral cysticercosis.• Detect specific antibodies in serum or CSF:1. ELISA using crude antigen extracted from the whole

cyst or its fluid, or using purified antigen fractions.2. immunoblot • Biopsy

V. Treatment• Recommend combined antiparasitic and

anti-inflammatory therapy.

• Praziquantel: PO for 15-30 days,or

• Albendazole: PO for 30 ds.

• Cortisone to to reduce inflammatory reaction due to dying cysticerci.

• Surgical excision for ocular cysticercosis, muscular and SC cysticerci

• CNS cases; non responders to drug.

VI. Prevention and Control• Prevent infection of man from pigs

Thorough cooking or freezing of pork.• Prevent infection of man from man

A. Prompt treatment of intestinal taeniasis solium.

B. Sanitary disposal of human excreta

C. Personal hygiene.

D. Proper washing of fruits and vegetable• Prevent auto infection of man

1. Avoid emetic drugs

Human tissue cestodiases

Final hosts

Adult worm Intermediate hosts

Larval stages

1st Larva 2nd Larva

Dogs, cats

Spirometra mansonoides

Man, frogs

mammals

Procercoid

(Cyclops)

Sparganum

Man Taenia solium Man, pig Cysticercus cellulosae

Dogs, wolves, foxes

Multiceps multiceps

Man, Rabbits sheep

Coenurus cyst

Dogs Echinococcus granulosus

Man, Sheep camels

Hydatid cyst

cats, foxes

Echinococcus multilocularis

Man, rodents

Alveolar hydatid cyst

Tissue cestodes: larvae, their adults and hosts

CoenurosisInfection of human tissue by Coenurus cerebralis;

Larva of Taenia multiceps

I. Biology• Final Hosts are dog, wolf and

fox : They harbor the Adult tapeworm that resembles Taenia .in their intestine.

• Man: harbors the cystic larva only and acts only as dead end intermediate host.

• Habitat in man: Cysts exist in all organs but more in eyes and brains.

• Exit stage: None, but cyst can be excised surgically.

• Exit stage from final hosts: Taenia like eggs

Cyst has multiple scolices, but no daughter cysts

I.B

iolo

gy: l

ife c

ycle

II. Epidemiology:• Distribution: North and east Africa, Zaire, USA

and England.

• Intermediate hosts: sheep, rabbits and man occasionally.

• Reservoir hosts: herbivores like sheep, Rabbits.

• Infective stage: egg of Taenia multiceps.

• Mode of infection: ingestion of fruits and vegetable contaminated by eggs of Multiceps.

III. Host parasite relationship• The transparent vesicle like cyst is space

occupying lesion that measures few mms to 5 cms.

• It has multiple scolices, but no daughter cysts.• Pathology depends on the site • If it tolerates mechanical pressure; no symp.• Muscle and SC tissues: painless nodules• Brain, eye and spinal cord are less tolerant sites;

so clinical picture develops:1. In brain: fits, headache, and hemi-plegia.2. In the eye: disturbed vision.

3. In spinal cord: paraplegia.

Coenurus excised from enucleated eye

IV. Diagnosis

• Imaging: X-ray, CT, and MRI.

• Recovery of the cyst by surgical excision.

• Ophthalmoscopic examination.

V. Treatment• Surgical removal of the coenurus

effectively treats intracranial and ocular coenurosis in most cases.

• Medical 

• praziquantel.

• The drug of choice is albendazole

VI. Control• Prevention of infection of the dogs from

rabbit and sheep by1. Proper carcass disposal of potentially

infected intermediate hosts.• Prevention of man infection from dogs1. Elimination of stray dogs.2. Treatment of pet dogs.3. Avoid contact with dogs.4. Thorough washing of vegetable and fruits5. Personal hygiene.

Hydatid diseases

1.Cystic hydatid disease (cystic echinococcosis)

• Ecchinococcus granulosus

2.Alveolar hydatid disease ( alveolar echinococcosis)

• E. multilocularis

3.Polycystic hydatid diease.

• E. vogeli and oligarthus.

I. Biology• Two species Echinococcus: 1. Unilocular larva (hydatid cyst): of E. granulosus2. Multilocular larva (alveolar hydatid cyst): of E.

multilocularis.• Final hosts are canids: The adults exist in their

intestine.• Human never acts as final host of these worms.• But Man can harbor the larva in his tissue to act as

blind end intermediate host.• Habitat in man: liver (65%), lung (25%),and

kidneys, bone, heart and brains (10%).• Exit stage: none, but hydatid cyst, hydatid sands

can be obtained by excision or by puncturing.

I. Biology

Life cycle of Echinococcus granulosus

II. Epidemiology• Distribution: areas of sheep & camel raising.• Intermediate hosts: herbivores; sheep, camels,

Cysts in cattle are sterile. They do not act as IH.

• Human is dead end intermediate host• Reservoir host: sheep and camels.• The infective stage of man: The taenia like egg of

E. granulosus in feces of dogs.• Mode of infection of man: ingestion of foods

contaminated by eggs.• The infective stage of the final host (dogs): the

hydatid cyst.• Mode of infection of dogs: ingestion of meat of

animals infected by the larva (hydatid cyst).

III. Host parasite relationship• Pathogenecity:• Space occupying lesion:1. The growing cyst produce pressure atrophy of the

surrounding tissues, leading to organ dysfunction. 2. This effect depends on the size and site of the cyst3. The most affected sites: liver (65%), lung

(25%),and kidneys, bone, heart and brains (10%).• Rupture of cyst:1. Immune response• Immediate hypersensitivity reaction (Type I): slow leakage causes allergic features & rupture of

the cyst causes anaphylactic shock.2. Metastasis• The rupture may lead to metastasis of secondary

cysts in other organs

III. Host parasite relationship• Pathology:• Size : unilocular cyst 1-

10 cm.• Wall of the cyst is

formed of 3 layers:1. Outermost fibrous layer

by the host2. Laminated non cellular

layer3. Inner germinal from

which scolices develop• Content: fluid, scolices,

brood capsule, and daughter cyst

III. Host-parasite relationship• Clinical picture: depends on site and size of cyst. • Mostly asymptomatic• Symptoms take years to develop (5-20)1. Liver cysts: hepatomegaly & obstructive jaundice. 2. pulmonary cysts: cough hemoptysis & abscess. 3. Kidney cysts: renal dysfunction and scolices appear

in urine.4. In bone may induce spontaneous fracture.5. Brain cysts: intracranial pressure and epilepsy6. Minimal leakage of the cyst Contents produces

urticaria and other allergic manifestation.7. Rupture of the cyst: leads to anaphylactic shock,

death.

IV. Diagnosis1. Imaging tests: Sonography, and CT. They with

history and eosinophilia are almost diagnostic.2. Aspiration to detect hydatid sand; brood capsules,

protscolices3. Histology of an excised cyst .4. By serological tests to detect specific antibodies. a. Initial screening tests with crude antigens using IHAT,

IFAT and ELISA techniques b. Confirmatory tests with purified antigens, ie. arc-5

Counter current immuno-electrophoresis (CIEP) and IB.5. Casoni test: • Intradermal injection of 0.2ml of sterile fresh hydatid

fluid gives erythematous wheel of ~5cm in diameter within 15-20 minutes.

IMAGING Aspiration

Serotesting: CIEP

V. Treatment• Treatment: • Inoperable cases: • Albendazole is given in 3 to 12 cycles of each

one month followed by a two week rest period.• Operable cases:• pre and post-operative albendazole to prevent

recurrence. • Removal either by partial hepatic resection,

pericystectmy or cystectomy• PAIR approach; Puncture→ Aspirate→ Inject

albendazole or hypertonic saline→ Reaspirate.

VI. Control• Prevention of infection of dogs from sheep

and camels by1. Sanitary disposal of the infected offal.• Prevention of man infection from dogs1. Elimination of stray dogs.2. Treatment of pet dogs.3. Avoid contact with dogs.4. Thorough washing of vegetable and fruits5. Personal hygiene

• Alveolar Echincoccosis

• Infection of human tissues by the larva of E. multilocularis

(Alveolar Hydatid cyst)

II. Biology Final hosts: Fox, wolves, dogs and cats

Habitat in the final host: small intestine Exit stage from the final host: Taenia

like eggs in faeces of FH. Man occasionally harbors the larval cysts

and acts as blind end IH. Habitat in man: liver, lung and brain.

Exit stage from man: none, the larval mass can only be recovered

surgically in early cases.

Final hosts

Intermediate Host

Man : blind end Intermediate host

I. Biology

II. Epidemiology Distribution: Europe and N.

America Intermediate hosts (IH):

rodents and human but human is dead end I.H.

Resrvoir hosts: rodents only The infective stage of man:

Taenia like egg in feces of FH. Mode of infection of humans:

accidental ingestion of eggs in foods, drinks.

Infective stage of FH (dogs): alveolar hydatid cyst in rodent..

Host parasite relationship

• Pathology:1.The site is usually the liver

2.Tumor like spongy mass with irregular, multi-vesicular, infiltrating structure consisting of small vesicles embedded in stroma of connective tissue

III. Host parasite relationship

• .Pathology continued;

3. The mass is without or with very thin limiting membrane,

4. Inner germinal epithelium proliferates in any direction invading surrounding tissues.

5. Cysts contains jelly like material rather than fluid.

6. If vena cava or portal vein are invaded. The lesion metastasizes to other organs e.g. lung and brain.

Alveolar hydatid cyst

III. Host-parasite relationship

• Clinical picture:

1.The larva grows very slowly so symptoms occur in patients over 50 ys.

2.These include right upper abdominal pain, hepatomegaly and jaundice.

3.Occlusion of IVC, and common bile duct produce fatal sequelae.

• Metastasis to brain and lung causes related symptoms

IV. Diagnosis1. Imaging: ultrasonography (US),CT, MRI.

• In CT the characteristic lesion is called geographic map with irregular contours and alternating hypodense and hyperdense areas.

2. Serotesting by ELISA or IB to detect specific abs using:

• fractionated E-S antigens of scolices of Em .

3. Wide scale Sero-testing to screen population at high risk allow early diagnosis of lesion.

• This can result in improvement in quality of management.

V. Treatment• The cases are usually discovered in late stages.• Surgery:

1. Late cases are almost inoperable.

2. Partial hepatectomy might provide solution

3. Liver transplantation is life saving.

4. Medical in late cases:• Drug therapy slows the growth and delays

complications • Life long continuous mebendazole • Intermittent albendazole (400 mg twice daily for 28

days alternating with 14-day rest period

VI. Control• Prevention of infection of FH; cats and dogs from

rodents by

• Rodent control

• Prevention of infection of man from cats and dogs

1. Stray dog elimination in endemic areas.

2. Treatment of pet animals.

3. Careful washing of vegetable and fruits

• Early diagnosis and treatment of human infection

• Mass serological screening of population in the endemic areas

Human tissue cestodiases

Tissue cestodiases1. Sparganosis : by sparganum; larva of

Spirometra.

2. Cysticercosis: by cysticercus cellulosae; larva of T. solium.

3. Cystic hydatidosis: by hydatid cyst; larva of Echinococcus granulosis.

4. Alveolar hydatidosis: by multilocular hydatid cyst; larva of E. multilocularis

5. Coenurosis: by Coenurus; larva of Multiceps multiceps

Mode of infection in tissue cestodiases• Pseudophyllidea:I. Sparganosis1. Ingestion of Water contaminated by Cyclops

containing procercoid larva.2. Ingestion of meat of IH infected with sparganum

larva.3. Skin or mucous membranes contact with meat of IH

infected with Sparganum larva• Cyclophyllidea:• Cysticercosis:• Ingestion of egg of T. solium in human's feces

contaminating vegetables or food:

Mode of infection in more Cyclophyllidean tissue cestodes

o Ingestion of Taenia like egg in feces of dogs contaminating vegetables or food:

2. Coenurosis: dog's feces: (eggs of Multiceps)

3. Cystic hydatidosis: dog's feces: (eggs of E. granulosus)

4. Alveleolar hydatidosis: dog or cat's feces: (Eggs of E. multilocularis)

  Spar-ganosis

Cysti-cercosis

Hyda-tidosis

Alveolar Hydatidosis

Coen-urosis

Final host Dogs, cats man dogs Dogs, cats dogs

Adult worm Spirometra T. solium E. granulosus

E. multilocularis

Multiceps

1st IH Cyclops Pigs

man

Sheep

man

Rodent

man

Sheep

man2nd IH

(paratenic)Frogs

(man)

nil nil nil nil

Inf. stage of man

Procercoid

sparganum

Taenia egg

Taenia like egg

Taenia like egg

Taenia like egg

Exit stage None None None None NoneDiagnosis Imaging, Biopsy, and sero-testing

Summary of Epidemio-Biologic Aspects of Tissue Cestodes

Outline of life cycles of cestodes

Human tissue

cestodes

Human

Intestinal

cetodes