Tapeworms

Question 1

Cestodes

Answer 1

Tapeworms that have hooks and suckers on their mouth

Only seen in raw/undercooked pork/beef/fish

Question 2

Taenia saginata and taenia sodi

Answer 2

Both are tapeworms

• saginata = mild diarrhea and ab pain or asymptomatic presentation. Seen in undercooked beef
• sodium = mild diarrhea and ab pain (never asymptomatic). Seen in undercooked pork

Saginata cant be spread once infected in humans (dead-end host)

Solium can be spread once infected in humans (fecal-oral route)

solium (not saginata) produces “cysticercosis” which is where cysts from solium are found in muscles/skin/organs and brain

Question 3

Diphyllobothrium Latum

Answer 3

Fish tapeworm that is ONLY seen in undercooked or raw fish
- larvae look like gains of rice (plerocercoids)

Can get up to 10 meters long when fully adult and can release up to 1 million eggs/day in intestines

Symptoms:

• mild GI discomfort and weight loss
• B12 deficiency and megaloblastic anemia (absorbs B12 vitamin, so host is deficient naturally)

Question 4

Echinococcus granulosus

Answer 4

Dog/sheep tapeworm that produce hydatid cysts
- cysts when they grow, can get massive (apple-cantaloupe sized) so symptoms are usually only present due to this mass effect of growth

• *even though the cysts are most commonly in the liver and lungs (can be seen anywhere though), you CANNOT biopsy liver or lungs for conformation.**
• this can burst the cysts and cause anaphylactic shock due to massive IgE reactions

Question 5

Trematodes

Answer 5

Are leaf-shaped flukes that are hermaphrodites

also called “liver flukes” and the usual host is snails.

Question 6

Colonorchis sinensis

Answer 6

A fluke that is found in undercooked/raw fish
- is endemic to Asia, but incidence is slowly increasing worldwide

Encrypt in stomach and gut and eventually migrate to the biliary tree.
- mature in the biliary tree and parasites damage bile ducts

**infection dramatically increases the risk of developing cholangiocarcinoma

Question 7

Schistosoma

Answer 7

Long worms that are 6-17mm that live over 10 years in the venous system
- “valentines day worm” since male and female worms stay with each other

3 subtypes:

1) mansoni
- inferior mesenteric veins of the large intestines lives in
- has a “lateral spine” in its ovum

2) japonicum
- inferior and superior mesenteric veins of the small intestines
- has no spine in its ovum

3) haematobium
- urinary bladder and Urinary tract veins
- *high risk of developing squamous cell carcinoma if chronic infection
- has “terminal spine” on ovum

Question 8

Symptoms of schistosoma

Answer 8

intially start in the veins and either get lodged into the liver or gets excreted out of the host

• *produces granulomatous reaction and fibrosis of the liver and portal HTN**
• always shows Hepatosplenomegaly

Symptoms: (rest of symptoms are 2-12 weeks after exposure)

• extreme pruritis (within 1 hr)
• fever/chills/malaise
• diarrhea
• “katakana/snail fever”

Diagnosis:

• eosinophila and past history
• see eggs on microscopy to confirm