Cestodes Flashcards by Keizel Galupo

Adult worms of the following cestodes are seen in the intestine of man, EXCEPT;

T. solium
E. granulosus
D. latum
Hymenolepis
None

E. granulosus

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The parasitic tapeworm transmitted by inadequately cooked freshwater fish is:

D. latum

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A 30-year old patient reported in the emergency room with complaints of fatigue, weakness, diarrhea, and numbness of extremities. The peripheral blood film revealed megaloblastic anemia and stool exam showed yellowish-brown operculated eggs. Which of the following parasites is likely to be the cause of the disease?

D. latum

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Operculated eggs are produced by:

D. latum

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Because of the similarities between the ova of T. solium and T. saginatam specific diagnosis can be made thru:

Demonstration of scolex

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What is/are the drug of choice for T. solium infection?

Praziquantel

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In the life cycle of D. latum, how many intermediate host is/are involved?

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Common name of D. latum

Fish tapeworm

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Bovine cysticercosis can be prevented thru the following measures, EXCEPT;

Thorough cooking of meat
Proper sanitary disposal of feces
Meat should undergo inspection
All
None

none

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The larval form of T. solium can be seen in:

Pigs

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The following tapeworms possess armed rostellum, EXCEPT;

D. caninum
T. solium
E. granulosus
T. saginata
None

T. saginata

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In which of the following cestodes man can act as the intermediate host?

T. solium (man can be DH/IH)

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Parasite-induced pernicious anemia is seen in infection with:

D. latum

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Encysted larva of T. solium that can be present in measly pork:

Cysticercus

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What is/are the intermediate host/s of Taenia saginata?

Cattle

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Fertilized eggs that are broadly oval, golden brown in color, some can be mammilated, and classified as soil transmitted helminths. Identity is:

Ascaris lumbricoides

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A roundworm acquired from the ingestion of meat containing the encysted larvae causing the encystment of the larvae in human striated skeletal muscle. Identity is:

Trichinella spiralis

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Egg of this tapeworm is oval or sub-spherical with 4 to 8 polar filaments, resembles like a “fried egg”. Identity is:

Hymenolepis nana

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The egg of this parasite was 1st discovered in the Philippines. Eggs are flat with bi-polar plug, peanut-shaped and presence of striated cell wall.

Capillaria philippinensis

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Asymmetrical nematodal egg with one side flattened and the other convex with translucent shell. Identity is:

Enterobius vermicularis

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A pseudophyllidean eggs that is usually yellowish brown in color with a moderately thick shell and an inconspicuous knob and an operculum.

D. latum

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The eggs of an STH that are barrel-shaped, with protruding bipolar plugs and the ova are unsegmented.

Trichuris trichiura

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The egg of this STH is ovoidal (egg-shaped), thin-shelled, colorless and passes 4-8 cell stage in the feces.

Hookworm

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Tapeworm’s egg that has three pairs of hooklets and a striated outer shell resembling like kiwi slices. The eggs of the two species cannot be differentiated. Identity is:

Taenia

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A dog tapeworm's egg which is spherical in shape, thin-shelled with hexacanth embryo, and are passed out in packets containing 8-15 eggs. Identity is:

Dipylidium caninum

Which among the statement is/are false about cestodes: A. Majority are long, unsegmented and resemble like tapeworms B. Majority are long, segmented and resemble like tapeworms C. Dorso-ventrally flattened D. Adult worms are found in the intestinal canal of man and animals E. None

This region in an adult worm is provided with suckers & sometimes with hooks that serves as organs of attachment.

Head/scolex

This is the region of growth in an adult worm.

Neck

This is referred to as the body/trunk of the adult worm.

Strobila

The strobila consists of segment called _____________

proglottids

T or F. Cestodes are not separate (monoecious)

True

What are those that are absent and present in cestodes?

Absent: Alimentary canal Present: Excretory & nervous systems; reproductive system

A type of segment of the strobila where male and female organs are not differentiated.

immature segment

A type of segment of the strobila where the male and female organs have become differentiated

mature segment

A type of segment of the strobila where the uteri are filled with eggs

gravid segment

A classification of cestodes that possess false or slit-like grooves called bothria

Pseudophyllidean cestodes

This is classified as the only pseudophyllidean cestode.

Diphyllobothrium latum (D. latum/fish tapeworm)

What is the larval stage for pseudophyllidean cestodes (D. latum)?

Plerocercoid in man

A classification of cestodes that possess cup-like round suckers called acetabula.

Cyclophyllidean

Common name for Taenia saginata

Beef tapeworm

Common name for Taenia solium

Pork tapeworm

Common name for Hymenolepis nana

dwarf tapeworm

Common name for Hymenolepis diminuta

Rat Tapeworm

Common name for Dipylidium caninum

Double Pored Dog Tapeworm

Larval stage in man of Echinococcus granulosus & Echinococcus multilocularis

Hydatid cyst

Larval stage in Man of Taenia solium

cysticercus cellulosa

Larval stage in man of multiceps multiceps

coenurus cerebralis

Larval stage in man of multiceps glomeratus

coenurus glomeratus

These are large worms consisting of a long chain of segments

Pseudophyllidean cestodes

Adult worm is yellowish grey in color. Dark central marking in the strobila are due to the egg-filled uterus. It measures 3 to 10 meters in length and its life span is for a period of 5 to 15 years.

D. latum

Scolex is spoon-shaped or spatulate and has no rostellum and no hooklets.

D. latum

Its neck is thin and unsegmented and is much longer than the head

D. latum

Its uterus at the center of the segment appears in the form of a rosette.

D. latum

It contains abundant granules and unsegmented ovum. It is inconspicuous operculum at one end and a small knob at the other end.

D. latum

T or F. Diphyllobothrium latum floats in saturated solutions of common salt.

False. It doesn't float.

The first stage larva of D. latum

Coracidium; ciliated oncosphere

Second stage larva of D. latum

Procercoid (found inside cyclops)

The first intermediate host for D. latum

Cyclops

Third stage larva of D. latum

plerocercoid (sparganum)

The second intermediate host of D. latum.

Fresh water fish - perch, trout, salmon, pike

Final host of D. latum

man, dog, cat (in the small intestine)

Infection of this cestode causes G.I. disturbances and anemia. It causes megaloblastic anemia since vit B12 is absorbed by worm.

D. latum

The disease caused by drinking water containing infected copepods.

D. latum

Unarmed tapeworm of man

T. saginata

Adult worms are white and semi-transparent. It measures about 4-10 meters of sometimes up to 25 meters. It can live up to 10 years or more.

T. saginata

It consists of 1000 to 4000 proglottids. Its common genital pore is marginally situated. Its vagina is provided with a sphincter muscle. Furthermore, gravid proglottid consists of a uterus and a central longitudinal stem with 15-20 lateral branches

T. saginata

Its free gravid proglottid crawls out of the anal orifice and oviposits on the perianal skin

T. saginata

Liberated by rupture of ripe proglottids, no uterine opening, spherical and having a thin, outer transparent shell with its inner embryophore is brown, thick walled and radially striated

T. saginata ova

It has an oncosphere with 3 pairs of hooklets (inside the eggshell). It doesn't float in saturated salt solutions and eggs are resistant and remain viable for 8 weeks.

T. saginata

FH & IH of Taenia saginata

FH: man IH: cattle, cow buffalo

Its adult worm is irritated by alcohol

T. saginata

Pathogenesis of T. saginata (TaPaMi EHWW LPO)

Taeniasis Passage of proglottids in stool Mild irritation Epigastric pain Hunger pangs weightloss weakness loss of appetite pruritis ani obstruction in intestine

Its eggs resemble kiwi slices

T. saginata

What is the treatment for T. saginata?

Praziquantel

This spp is common among those eating raw or insufficiently cooked "measly pork"

T. solium

Man can both be the DH/IH in this type of cestode.

T. solium

Scolex is globular in outline with 4 circular suckers. Scolex has a rostellum armed with a double row of alternating large and small hooklets. Rostellar hooklets are shaped like daggers or Arabian poniards.

T. solium

Vaginal opening is not guarded by a muscular sphincter.

T. solium

T or F. Taenia Saginata is infective to man as well as pigs.

False

Thick brown striated embryophere surrounding a hexacanth embryo.

T. saginata ova

Treatment for T. solium

Praziquantel

Also known as hydatid worm

Echinococcus granulosus

T or F. In Echinococcus granulosus, man harbors both the cyst and the adult worms which however is found in the intestine of dogs and canines.

False. it only harbors the cyst and not the adult worms

T or F. Echinococcus granulosus is compsoed of a scolex, neck and strobila having three segments -- immature, mature, gravid.

True

Scolex bears 4 suckers and protrusible (can be extended) rostellum with 2 circular rows of hooks

E. granulosus

Ovoid in shape, resemble Taenia ova, Hexacanth embryo with 3 pairs of hooks

E. granulosus

E. granulosus is infective to:

man, cattle, sheep & other herbivorous animals

DH & IH of E granulosus

DH: dog, wolf, fox, jackal IH: sheep, pig, cattle, horse, goat

Its most common site of involvement is the liver

E. granulosus

Its rupture of cyst in the lungs may present coughing accompanied by allergic reactions

E. granulosus

Echinococcus granulosus cyst

unilocular hydatid cyst

Echinococcus multicularis

alveolar cyst

What is the PAIR technique for inoperable cyst of E. granulosus?

Puncture, Aspiration, Injection, Reaspiration Invervention Albendazole

3 testes in each mature segment. Uterus is sac-like and transverse. Eggs possess two membranes' outer membrane is thin and transparent.

Hymenolepis spp

What is the larval syage of Hymenolepis spp.?

Cysticercoid

It has a small bladder containing the invaginated head proximally and a solid, elongated portion as a caudal appendage.

Hymenolepis spp

Smallest tapeworm infecting man

H. nana

Only human tapeworm that can complete its life cycle in a single host where man can harbor both the adult and larval stages of the parasite.

H. nana

This is found in the ileum & has a delicate strobila

H. nana

Subglobular, 4 suckers, provided with a short retractile rostellum armed with a single row of 20-30 hooklets where its rostellar hooklets are shaped like tuning fork.

Scolex of Hymenolepis nana

What differentiates H. nana & H. diminuta?

H. nana has polar filaments emating from little knobs at either end of the embryophore. Also, H. diminuta requires an intermediate host

H. nana has two mode of transmission. What happens during direct & indirect pathway transmission?

Direct: Host ingests eggs that hatches in the duodenum Indirect: Accidental ingestion of infected arthropod IH like rice and flour beetles in which cysticercoid larvae are released and develop into adult worms in the small intestine of the host

Pathogenesis of H. nana (ImAH DAPA PD)

immunological response to the parasite asymptomatic for light worm burden headache dizziness anorexia pruritus of the nose and anus abdominal pain pallor dequamation

T or F. In H nana, proglottids are recovered because they undergo degeneration prior to passage.

False. They are not recovered.

Common parasite of rats and mice.

Hymenolepis diminuta

Larval stage of H. diminuta

cysticercoid passed in fleas

Outer shell is yellowish in color, inner embryophere has 2 knob-like thickenings, no polar filaments

H. diminuta

T or F. The longer the tail of H. diminuta, the more mature the cysticercoid.

true

This stage is found inside an insect such as the mealworm.

H. diminuta

Worm burden of H. diminuta in man

Common among children due to ingestion of infected grain beetles, dried fruits, flour and cereals

H. diminuta

Presence of bilateral genital pores in each segments (2 entrances)

Dipylidium caninum

Common intestinal parasite of dogs

Dipylidium caninum

Small and globular, 4 deeply cupped elliptical suckers, protrusible/retractile rostellum. Furthermore, rostellum has 1-7 rows of rose thorn shaped hooklets

D. caninum

Have size and shape of pumpkin seeds and is filled with capsules or packets of 8-15 eggs enclosed in embryonic membrane.

D. caninum gravid proglottids

Released by contraction of proglottids or disintegration outside the host. It is spherical, thin shelled, and with a hexacanth embryo.

D. caninum ova

1st IH of D. caninum and where they're from. Ctenocephalides canis

dog flea

1st IH of D. caninum and where they're from. Ctenocephalides felis

cat flea

1st IH of D. caninum and where they're from. pulex irritans

human flea

1st IH of D. caninum and where they're from. Trichoedectes canis

dog flea

2nd IH of D. caninum

Dog (cysticercoid)

Symptoms of D. caninum (SEDAA)

Slight intestinal discomfort epigrastric pain diarrhea anal pruritus allergic reactions