Trematodes

Question 1

Name the genus and species of the trematode commonly known as the Chinese Liver Fluke.

Answer 1

Clonorchis sinensis

Question 2

Name the genus and species of the trematode known as the Sheep Liver Fluke.

Answer 2

Fasciola hepatica.

Question 3

Name the genus and species of the trematode known as the Lung Fluke.

Answer 3

Paragonimus westermani

Question 4

This trematode may encyst in the lungs and produce eggs that can be detected in sputum and stool.

Answer 4

Paragonimus westermani

Question 5

Infections with this trematode are commonly acquired by ingestion of raw or poorly cooked crabs or crayfish.

Answer 5

Paragonimus westermani

Question 6

This group of trematodes are very difficult to distinguish in the egg stage. You might receive a lab report naming them all.

Answer 6

Clonorchis sinensis – Liver; Opisthorchis felineus – Liver; Opisthorchis viverini – Liver; Metagonimus yokogawai – intestine; Heterophyes heterophyes – intestine

Question 7

These two trematodes are known as blood flukes, their eggs are found in stool specimens.

Answer 7

Schistosoma mansoni; Schistosoma japonicum;Their eggs are laid in the blood vessels near the intestinal wall, and eventually work their way into the stool.

Question 8

This trematode is an exception to the “stool for O&P rule”. You want to examine urine to detect this infection.

Answer 8

Schistosoma hematobium

Question 9

Lack of this intermediate host precludes the establishment of Schistosome infection in the continental U.S.

Answer 9

Species of snail.

Question 10

Infection with this trematode is acquired by the direct penetration of human skin by the cercariae.

Answer 10

Schistosoma mansoni; Schistosoma hematobium; Schistosoma japonicum

Question 11

Ingestion of raw or poorly cooked infected fish can lead to infection with this trematode.

Answer 11

Clonorchis sinensis

Question 12

Ingestion of water plants containing metacercariae can lead to infection with this trematode.

Answer 12

Fasciola hepatica

Question 13

This trematode dissease is also call bilharzia.

Answer 13

Schistosomiasis

Question 14

Schistosomes are called blood flukes. The specimens used to diagnose schistosomes are stool and urine. Why don’t we collect blood since the worms live in blood vessels?

Answer 14

Female worms deposit eggs in the portal vessels and perivesical systems. These sharaply barbed eggs are pushed toward the lumen of the intestine (or bladder), break through and eggs sill into urine and fecal flow.

Question 15

Name schistosome(s) recovered from feces.

Answer 15

Schistosoma mansoni Schistosoma japonicum

Question 16

Name schistosome(s) recovered from urine.

Answer 16

Schistosoma hematobium

Question 17

Which schistosome egg has: A: Large lateral spine B: Terminal spine C: Small, inconspicuous spine on lateral surface

Answer 17

A: Schistosoma mansoni has a large lateral spine. B: Schistosoma hematobium has a terminal spine. C: Schistosoma japonicum has an inconspicuous spine on lateral surface.

Question 18

These members of platyhelminthes (flatworms) penetrate snails and multiply in sporocysts to increase their numbers.

Answer 18

Schistosomes.

Question 19

Penetration of human skin by ceercariae which are species specific for another host (eg waterfowl) results in a condition known as……

Answer 19

Swimmer’s itch.

Question 20

True/False: The greatest pathology produced by Schistosoma mansoni is caused by adults consuming the blood of the host.

Answer 20

False. Adults produce many many eggs which are highly antigenic. The human body responds to this antigen and damages tissue. Eggs cut tissue and can lead to secondary bacterial infection. Eggs are the source of pathology.

Question 21

Gross, visible blood in the urine would cause you to add this parasite to your differential diagnosis.

Answer 21

Schistosoma hematobium

Question 22

This trematode is commonly known as the lung fluke.

Answer 22

Paragonimus westermani

Question 23

Ingestion of raw or poorly cooked crabs or crayfish can lead to infectin with this trematode.

Answer 23

Paragonimus westermani

Question 24

True/False: Lung flukes migrate in the human by flowing along with the bloodstream to the lungs where they settle out and encyst.

Answer 24

False. Immature flukes penetrate into the abdominal cavity, migrate to the lungs by penetrating the diaphragm and mature to adults. They can also migrate to other tissues - brain, muscle, liver, skin, testes, - but eggs can’t pass to the external environment from these sites so the eggs can go undetected.

Question 25

True/False: Trematodes (flukes) are exclusively parasites of internal organs.

Answer 25

False. Fasciolopsis buski, Heterophyes and Metagonimus are intestinal flukes. If you subscribe to the description of the intestine being a tube within a tube, then these flukes aren’t inhabiting internal organs.

Question 26

Name a parasite acquired by eating waterplants contaminated with metacercariae.

Answer 26

Fasciolopsis buski or Fasciola hepatica

Question 27

True/False: Fasciolopsis buski sucks blood from intestinal tissue and causes servere anemia.

Answer 27

False. Fasciolopsis buski attaches to epithelium, feeds on intestinal tissue. Light infections can cause intermittent diarrhea. Heavy infections can produce continuous diarrhea and hemorrhage. patients complain of abdominal pain - simulates peptic ulcer.

Question 28

What is the causative agent of sheep liver fluke infection?

Answer 28

Fasciola hepatica

Question 29

What is the genus and species of the Oriental Lung Fluke?

Answer 29

Paragonimus westermani

Question 30

Name the trematode egg that is characterized as having “wide shoulders”.

Answer 30

Paragonimus westermani

Question 31

Name parasitic infections (genus an species) I might acquire by eating raw or poorly cooked crab or crustaceans.

Answer 31

Paragonimus westermani

Question 32

What is the agent responsible for bilharzia?

Answer 32

Schistosoma mansoni

Question 33

Which trematode egg has a prominent lateral spine?

Answer 33

Schistosoma mansoni

Question 34

Which trematode egg has a terminal spine?

Answer 34

Schistosoma hematobium

Question 35

Which trematode egg has an inconspicuous spine?

Answer 35

Schistosoma japonicum

Question 36

What is the specimen of choice for Schistosoma hematobium?

Answer 36

Urine

Question 37

What is the specimen of choice for Schistosoma mansoni?

Answer 37

Stool for O&P.

Question 38

How are schistosomes acquired?

Answer 38

Direct penetration of larvae.

Question 39

Blood in the urine would be associated with which schistosome?

Answer 39

Schistosoma hematobium

Question 40

Pipe stem fibrosis may occur with which schistosome?

Answer 40

Schistosoma mansoni

Question 41

Name trematodes found in the blood stream.

Answer 41

Schistosoma mansoni, Schistosoma japonicum, Schistosoma hematobium. (Their eggs can be found elsewhere. The adults are in the blood - hence the term blood flukes.)

Question 42

Name a trematode found in the liver.

Answer 42

Fasciola hepatica

Question 43

Name a trematode found in the lung.

Answer 43

Paragonimus westermani