Parasites-Cestodes (Tapeworms)

Question 1

What are the traits of Cestodes (tapeworms)?

Answer 1

Scolex (head). Segmented body (Proglottids). suckers (Rostellum). monoecious. Eosinophilia. No body cavity. No GI tube.

Question 2

What are the unique structural characteristics of Taenia Saginata?

Answer 2

(Beef Tapeworm)

scolex with 4 suckers. NO HOOKS.

Question 3

What is the source of Taenia Saginata? What form is taken in by humans? And what does it cause and why?

Answer 3

1. (Beef Tapeworm)= ingestion of undercooked beef
2. ingest cystcerci
3. Asymptomatic b/c cystcerci= (no cystercerosis in humans)= humans act as hosts only to adult tapeworms

Question 4

How do you treat Taenia Saginata?

Answer 4

(Beef Tapeworm)

* Praziquantel. Albendazole.

Question 5

What is the most common tapeworm in the US? And what are its unique features?

Answer 5

• 1. Hymenolepsis nana (Dwarf tapeworm)

2. only TAPEWORM to complete its life cycle in 1 host (both larval and adult forms found in humans)

Question 6

How is Hymenolepsis nana transmitted?

Answer 6

(dwarf tapeworm)
Direct= ingest eggs—hatch in duodenum
Indirect= ingest infected arthropod

Question 7

What does Hymenolepsis nana cause?

Answer 7

(dwarf tapeworm)

headache. pruritis. (symptoms due to immune response).

Question 8

What is the source of Taenia Solium? And what are its unique structural characteristics?

Answer 8

1. pork (pork tapeworm)

2. scolex with 4 suckers and hooklets.

Question 9

What is the intermediate host and the definitive host of taenia solium?

Answer 9

(pork tapeworm)

1. both= humans

Question 10

What is the pathogenesis of Taenia solium?

Answer 10

(pork tapeworm)

ingest undercooked pork—larvae penetrate intestines—enter blood— encyst in brain

Question 11

What does taenia solium cause?

Answer 11

(pork tapeworm)
1. hydrocephalus. motor spasms. paraplegia. loss of vision. chronic meningitis. seizures.
(“swiss cheese” brain)

Question 12

How do you treat Taenia Solium? And what is important to consider in treatment?

Answer 12

(pork tapeworm)

• 1. Praziquantel. Albendazole. (surgical resection if possible)
     
     2. treatment will kill cysts, but death of larvae can increase inflammation, edema, and already present symptoms

Question 13

What are the unique characteristics of Diphyllobothrium latum?

Answer 13

1. fish tapeworm
2. yellow with dark markings.
3. scolex with 2 suckers
4. longest tapeworm (3-15 M. 5-15 yrs.)

Question 14

How do humans get Diphyllobothrium latum/. And What is its cycle of transmission? What is/are the definite host(s)?

Answer 14

(fish tapeworm)

1. eat raw/undercooked fish
2. eggs—crustacean—fish—human
3. definite hosts= dogs and humans

Question 15

What does Diphyllobothrium latum cause?

Answer 15

(fish tapeworm)
mostly asymptomatic, but can cause ab. discomfort.
* may increase B12 uptake leading to megaloblastic anemia (patients with malabsorption issues are at risk).

Question 16

What are the unique structural traits of Echinococcus granulosis?

Answer 16

(Dog Tapeworm)

scolex with 3 proglottids. rostulum. 4 suckers. 2 rows of hooks

Question 17

What is/are the definitive host(s) for Echinococcus granulosis? What populations are at risk?

Answer 17

1. Dogs and sheep

2. Hunters and Sheppards

Question 18

What is the pathogenesis of Echinococcus granulosis in the intermediate host?

Answer 18

(dog tapeworm)

1. larval cyst develops in organs (usually liver)—travels to brain. (Alveolar cysts commonly caused by “fox tapeworm”)

Question 19

What does Echinococcus granulosus cause?

Answer 19

(dog tapeworm)

• usually asymptomatic, but can cause hydatid cysts.
• [after 10 yrs, cyst may be 8-10 cm. if so, symptoms will develop= compress vital structures. erode into biliary tract/bronchus. get superinfections of cysts]
• if cysts leak/rupture= anaphylactic rxn (fever. hypotension).