GI cestodes and trematodes Flashcards Preview

Year 1 Microbiology > GI cestodes and trematodes > Flashcards

Flashcards in GI cestodes and trematodes Deck (22):
1

What are the three basic structures of the tapeworm?

1. Scolex - attachment 2. Neck - new segment generation 3. Body (strobila) - a long segmented structure

2

What is the cause of beef tapeworm?

Taenia saginata

3

What is the transmission for beef tapeworm (taenia saginata)?

Ingestion of encysted larvae in undercooked beef

4

What is the diagnosis for taenia saginata?

Detection of proglottids or eggs in stool

5

What is the cause of pork tapeworm?

Taenia solium

6

What is the transmission for pork tapeworm (taenia solium)?

Ingestion of cysts from undercooked pork

7

How does extra-intestinal disease (cysticercosis) result from pork tapeworm (taenia solium)?

Ingestion of embryonated eggs

8

What are the properties of extra-intestinal pork tapeworm (taenia solium) infection?

1. Ingested eggs hatch in intestine and release infectious larvae which enter circulation to encyst in various locations 2. Space filling lesions cause localized inflammation 3. Neurocysticercosis - severe complication

9

What is the cause of fish tapeworm?

Diphyllobothrium latum

10

What is the transmission of fish tapeworm?

Ingestion of infectious larvae from undercooked fish

11

What are the symptoms of fish tapeworm (diphyllobothrium latum)?

1. Transient nausea 2. Abdominal pain 3. Diarrhea 4. Macrocytic anemia - B12 deficiency (rare)

12

What is the genus and species of dog tapeworm?

Echinococcus granulosus

13

What are the properties of dog tapeworm infection?

1. Humans are intermediate host 2. Acquired through exposure to dog feces

14

What is the pathogenesis of dog tapeworm?

1. Ingested eggs hatch in intestine 2. Larvae travel via blood stream to multiple body sites 3. Larvae create fluid filled cysts 4. Cysts must be surgically removed without breaking hyaline membrane

15

What are properties of trematodes?

1. Humans are definitive host 2. Freshwater snails are intermediate hosts 3. Larval forms released from snails encyst on fish, shellfish, or vegetation - acquired via ingestion

16

What are the features of fasciolopsis buski?

1. Transmission via freshwater aquatic plants 2. In small intestine cercariae excyst, attach to columnar epithelium and mature to egg laying adults (hermaphroditic)

17

What is the diagnosis for fasciolopsis buski?

Detection of eggs in stool

18

What are the two liver flukes?

1. Fasciola hepatica 2. Clonorchis sinensis

19

Where is the liver fluke fasciola hepatica found?

Larval forms encyst on freshwater vegetation

20

Where is the liver fluke clonorchis sinensis found?

Larval forms encyst in fish

21

What are the features of fasciola hepatica infection?

1. Acquired through ingestion of aquatic plants 2. Migration through liver may induce tenderness and hepatomegaly 3. Fever and eosinophilia common 4. Biliary obstruction may occur (jaundice)

22

What are the features of clonorchis sinensis infection?

1. Acquired through ingestion of undercooked fresh water fish with attached encysted cercariae 2. Light infections asymptomatic 3. Heavy infections - biliary obstruction, jaundice, hepatitis, hepatomegaly, gall stones 4. Endemic throughout Asia