Intestinal Cestode Concise Pharmacy

8/7/2019 Intestinal Cestode Concise Pharmacy

http://slidepdf.com/reader/full/intestinal-cestode-concise-pharmacy 1/32

Life cycle in human trematodes



Intestinal Cestodes

Dr Mohiedden M Abdul-Fattah



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 incyclops

4- 2nd larva

in fish

Intestinal cestodes

1-Adult in

intestine of

Man

Cyclophyllidea:

1.Taenia saginata2.T. solium

3.Hymenolepis

nana.

4.H. diminuta

5.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 twointermediate hosts in their life cycles:

(Cyclops as 1st IH and Salmon fish as 2nd IH.



OUTLINE OF LLIFE CYCLE IN INTESTINAL CESTODES



Taenia

saginata

1. Biology:

Final host: human.

Habitat: small intestine. Exit stage: mature egg or

gravid segments.

Diagnostic morphology of adult:

1. segmented 4-7 meter long

2. with globular scolex without

rostellum or hooks.

3. 4 circular suckers.

4. Each mature segment has

central tube shaped uterus.



Taenia Life Cycle



4. Lab Diagnosis:

Detection of either of the following in

stool: the non hooked scolex of the adult after

treatment,

The gravid segment (15 ± 20 branches on

each side) .

The egg: 30-40 µm, spherical, with outer

thick and inner thin shell and embryo.



2. Epidemiology

Distribution: cosmopolitan.

Intermediate host: cattle. Infective stage: Cysticercus bovis larva in meat.

Mode of infection: ingestion of under cooked

meat containing the infective stage. Reservoir host: None.

3. Host parasite relationship:

Light infections remain asymptomatic, but Heavier infections may produce abdominal

discomfort, epigastric pain, vomiting and diarrhea.



5. Treatment:

Praziquantel is the drug of choice,(10-

20mg/kg PO for single dose), or Niclosamide (1-2 g children and 4 g for

adults; for single dose).

Expulsion of scolex must be assured toassume a satisfactory treatment.

6. Control:

Thorough inspections of beef and pork, Adequate cooking or freezing of meat.

cysticerci do not survive temperatures below -10o

C and above 50o C.



Taenia

solium

Biology:

Man is the only final host but canact as blind end intermediate host

also. Habitat: small intestine

Exit stage from the final host:scolex, gravid segments and/or mature egg.

Diagnostic morphology

1. segmented 3-5 meter long

2. with quadrate scolex with 4 circular suckers.

3. It has rostellum with double rows of hooks.

4. Each mature segment has central

tube shaped uterus



Taenia solium Life Cycle



2. Epidemiology

Distribution: where pork is eaten.

Transmission

Intermediate hosts: pigs (mainly) and man (if swallowed

the eggs).

No reservoir hosts.

Infective stages:

Intestinal adult: - C. cellulosae larva

larval infection (cysticercosis): T. solium eggs.

Mode of infection:

1. Adult taeniasis solium: ingestion of infected pork.

2. Larva taeniasis solium (cysticercosis): If man ingests T. solium egg, cysticercus cellulosae

develops in human tissues.




Disease due to adult: mild enteritis with indigestion.

Disease due to larva: cysticercosis .

4. Lab diagnosis:

Adult: - Detection of the following in stool samples:

Gravid segment with 12 lateral branches.

scolex with rostellum having double rows of hooks

Eggs similar to that of T. saginata.

Cysticercosis: Imaging (sonar, CT) and serology



5. Treatment:

Intestinal:

A. Praziquantel is the drug of choice,(10-20mg/kg PO

for single dose), or

B. Niclosamide (1-2g for children and 4 g for adults;

(single dose).

Neurocysticercosis:A. albendazole (15mg/kg/day PO for 30 days)

B. Corticosteroids are used to control the inflammation

due to death of the larva.

Symptomatic cysticercosis outside CNS:

Surgery is the management of choice.

6. Control: like Taenia saginata.



Hymenolepis nana

1. Biology: Final hosts: Humans and rodents.

Habitat: small intestines.

Exit stage (diagnostic): mature egg. Life cycle and Diagnostic morphology:

segmented, 0.5 ± 1 cm long with retractile

armed scolex.



H.nana Life Cycle



2. Epidemiology:

Distribution: cosmopolitan. Children more than

adults.

Intermediate hosts: Fleas act as intermediate host

when its larva ingests the egg and cysticercoids

develops within its body cavity.

Reservoir hosts: rodents. Infective stage: egg.

Mode of infection: 1-Ingestion of foods and drinks

contaminated with egg. 2- Autoinfection.


Disease: mild enteritis and allergy to the worm

excretion. Heavy infection may cause diarrhea



4. Diagnosis:

By detection of eggs in stool sample.

Characteristics of egg: - 30-40 µm, round, colorless,

with hexacanth embryo and polar filaments.

5. Treatment:

6. Praziquantel is the drug of choice,(25mg/kg PO for

single dose), or 7. Niclosamide (1g - 2g for children and 4 g for adults;

for 7 days). There is relative resistance of

cysticercoids to drug therapy.

6. Control: Health education and personal hygiene.



Hymenolepis diminuta1. Biology:

Final Hosts: mainly

rats; occasionally man.

Habitat: small intestine

Exit stage (diagnostic):

the egg;

Diagnosticmorphology:

segmented, 90 cm long

with unarmed scolex.

Life cycle



2. Epidemiology: Distribution:

Common parasite of rats allover the world. Human is occasionally infected.

Resevoir hosts: rats

Intermediate hosts: grain beetles and cockroaches.

Infective stage: The cystic larva (cysticercoid).

Mode of infection: Ingestion of cereals, dried fruits

contaminated with insects containing the cysticercoid.

3. Host- parasite relationship: Disease: affects mainly children and may

suffer abdominal pain, diarrhea, insomnia

and convulsions.



4.Lab. Diagnosis:

Detection of the characteristic eggs in stool

samples. Egg characteristics: 60- 80 µm, round, yellow

brown, with hexacanth embryo and polar knobs.

5.T

reatment:Niclosamide (2g first day+ 1g daily for 6 days).

6.Control: health education and personal hygiene.



Dipylidium caninum1. Biology:

Final Hosts: mainly dogs and cats;occasionally man.

Habitat: small intestine.

Exit stage: eggs in feces within egg capsules

Life cycle and Diagnostic morphology: scolexwith retractile rostellum armed with 4-6 rows of

hooks, with cucumber like segments and length

of 30 cm.



Life Cycle of D. caninum



2. Epidemiology:

Distribution: Common parasite of dogs, cats.

Accidental in humans specially children.. Intermediate hosts: fleas (pulex) and dog louse.

Their larvae ingest the eggs passed in the faeces.

The eggs release onchospheres that develop into

cysticercoids in the haemocele of the adults.

Reservoir host: dog

Infective stage: The cystic larva (cysticercoid).

Mode of infection:1. Ingestion of cereals, contaminated with insects

containing the cysticercoid.

2. Accidental swallowing of the infected fleas.



3.Host - parasite relationship:

The worms affect mainly children that may

suffer abdominal pain.4.Lab. Diagnosis: - Detection of egg capsules; each

containing 8 ± 25 eggs. Or the segments in stool

samples.

5.T

reatment:N

iclosamide (2g first day+ 1g daily for 6days.

6. Control: health education and personal hygiene.



Diphyllobothrium latum

A. Biology:

Final host: Fish eating animal includinghuman.

Habitat: Attach to mucosa of ileum or

sometimes jejunum.

Exit stage: Immature egg or chains of mature segments.

Diagnostic morphology of adult:

segmented 3-10 meter long with scolex that

has no hooks, but with 2 elongated sucking

grooves.

Each mature segment has central rosette

shaped uterus.



Life cycle of D. Latum



B. Epidemiology:

Intermediate hosts: cyclops (1st I.H.) and

fresh water fish; salmon (2nd I.H ). Reservoir host: fish eating animals

Infective Stage: pleurocercoid larva in

muscle fish. Mode of infection: ingestion of

undercooked fish containing plerocercoid

C. Host parasite relationship:

1. Macrocytic anemia and neurological

problems of vitamin B12 deficiency are

seen in heavily infected individuals.



D. Lab diagnosis:

Detection of eggs in faeces (many).Yellowishbrown ovoid 70x40 µm with anterior operculum and posterior knob

long chains of segments with rosette shapeduterus.

E. Treatment:

1. Praziquantel is the drug of choice, (10-

20mg/kg PO for single dose), or 2. Niclosamide (1g -2g for children and 4 g for

adults; single dose).

F. Control:

1. Freezing for 24 hours.2. Thorough cooking or pickling of fish kills the

larvae.

3. Fish reservoirs should be kept free of rawsewage.



Man is usually infected by intestinal

cestodes when ingests the larvae exceptH.nana, infection occurs by eggs.

Psuedophyllidea (D. latum) needs twointermediate hosts in their life cycles (Cyclops

as 1st IH and Salmon fish as 2nd IH.All Cyclophyllidea must need one intermediatehost in their life cycle except H. nana.

1.The IH in Taenia is vertebrate host (cattle or pigs).

2.In Hymenolepis and Dipyllidium it is invertebrateinsects (fleas, beetle, cockroach)

Summary



OUTLINE OF LLIFE CYCLE IN INTESTINAL CESTODES

Documents

Intestinal Cestode Concise Pharmacy