GI cestodes

Question 1

3 basic structures of adult tapeworms

Answer 1

• scolex-founded head of worm-usually armed with suckers or hooks
• neck- the area from which new body segments are generated
• body (stobila)- a long segmented structure. individual segments are called proglottids

Question 2

what is in each segment of a tapeworm? what are the segments called

Answer 2

• ovaries and testes- become pure eggs

- proglottids

Question 3

what’s the beef tapeworm called and how does it infect?

Answer 3

• taenia saginata
• infected human defecates and cows eat dirty soil, egg reaches cow circulation and lodges into the muscle of cows and is called a cysticercus in muscle
• at this point a larval worm is released and tapeworms then grow in the intestines

Question 4

how is taenia saginata transmitted?

Answer 4

ingestion of undercooked beef containing encysted larvae

Question 5

how long can a taenia saginata live and how log can it get?

Answer 5

-25 yrs, 10-30 ft long

Question 6

symptoms, diagnosis, prevention of taenia saginata infection

Answer 6

symptoms- asymptomatic to mild abdominal cramps and feeling of fullness
diagnosis- ID of proglottids or eggs passed by infected individual
prevention- prevent cattle from being infected and fully cook meat

Question 7

what’s the name for the Pork Tapeworm? how does it infect

Answer 7

• taenia solium (like liem eating hotdogs pork)
• infects 1 of 2 ways
  1) infects via pig eating eggs shed by humans and eggs hatch in intestine and larvae enter circulation and lodge into muscle, pig eaten by human and infects -given to humans when pig undercooked =similar to beef tapeworm
  2) humans not sanitary and is infected and ingests eggs from self and then the eggs hatch in intestine and release infectious larvae which enter the circulation and travel to extra-intestinal places like eyes, lungs, brain etc and lodge there = creates space filling lesion and induces localized inflammation -called CYSTICERCUS

Question 8

what’s a severe complication of taenia solium infection

Answer 8

-neurocysticerosis lodging in brain where you get seizures and neuro probs

Question 9

Diagnosis and prevention of taenia solium?

Answer 9

Diagnosis-proglottids or eggs in stool
-CT scan, MRI if extraintestinal (cystericus)

prevention- fully cook pork, keep pigs away from human feces

Question 10

what’s the name for the fish tapeworm? how does it infect?

Answer 10

-Diphyllobothrium latum
pathogenesis =
1) infected human sheds eggs in freshwater
2) eggs eaten by crustacean
3) fish eat crustacean
4) humans eat fish- raw = infected

Question 11

where can diphyllobothrium latum be found?

Answer 11

Minnesota, Michigan, Fl, Ca

Question 12

symptoms of diphyllobothrium latum

Answer 12

-nausea, ab pain, diarrhea, infection with multiple tape worms can cause intestinal obstruction, macrocytic anemia b/c tapeworm LOVES B12

Question 13

diagnosis and prevention of diphyllobothrium latum

Answer 13

• diagnosis -eggs in stool

- prevention-cook fish, avoid feces with fish

Question 14

what’s another name for dog tapeworm and how does it infect humans?

Answer 14

• echinococcus granulosus
• humans are an accidental host- usually infected dogs shed feces and it’s eaten by sheep/goat/swine and live in them and when they die, dogs feed on them and life-cycle continue => humans substituted for sheep and larvae infect many organs causing lesions

Question 15

pathogenesis of echinococcus granulosus

Answer 15

• eggs hatch in intestine and larvae enter the circulation and lodge in multiple different body sites
• in tissues, larvae secrete a hyaline membrane and over time, a fluid filled cyst forms (often in liver. lungs, brain, bone marrow)

Question 16

signs and symptoms of echinococcus granulosus

Answer 16

-depend on location of cysts but ruptured cysts release large amounts of antigen and can induce and anaphylactic response

Question 17

what is fasciolopsis bucscki? how does it infect?

Answer 17

• intestinal fluke
• human sheds fluke into the environment and it reaches water where it is infects snails and then are shed by snails to attach to water chestnuts and humans eat the chestnuts and the fluke is excyzed in the duodenum and attaches to the mucosa of the small intestine where it lays eggs and they are shed in the feces

Question 18

where is Fasciolopsis buski found and how do humans get it?

Answer 18

• found in china, south east asia, and india

- humans acquire it be ingesting chestnut, freshwater aquatic plants and encysted cercariae attached

Question 19

symptoms of fasciolopsis buski?

Answer 19

• mild- (single worm) focal inflammation, intermittent diarrhea
• severe- (multiple)- continuous diarrhea, intestinal hemorrhage, ulceration and abscess formation

Question 20

diagnosis and prevention of fasciolopsis buski

Answer 20

• egg in stool
• prev- control snail pop, improved sanitation and restric harvesting of freshwater aquatic plants in contaminated areas

Question 21

Fasciola hepatica
what is it?
how does it infect?

Answer 21

• liver fluke
• eggs in feces infect snails and then swim to freshwater plants or snails and fish eat and humans eat fish
• eggs excyst in duodenum and the larvae migrate to the bile duct and then lodge in the mucosa of the intestinal wall where it lays more eggs that are shed into the feces

Question 22

how to get f. hepatica? what is it a parasite of and where it is found?

Answer 22

• ingestion of freshwater plants

- parasite of sheep, humans. and cattle

Question 23

symptoms of f. hepatica

Answer 23

• migration of liver may induce liver tenderness and hepatomegaly
• fever and eosinophilia
• bilary obstruction and JAUNDICE (hepatica)

Question 24

diagnosis and prevention of f. hepatica

Answer 24

diagnosis- eggs in feces

prevention- control snail pop, improved sanitation, restrict harvesting of aquatic plants from contaminated areas

Question 25

what is opisthorchis (clonorchis) sinensis 
what is it?
where it found?
how do you get it?
symptoms

Answer 25

• liver fluke
• asia- more than 25% infected
• get it via ingestion of fresh water FISH-undercooked
• mild- asymptomatic
• severe- can penetrate liver and cause hepatitis, hepatomegaly, jaundice, biliary obstruction, gall stones
• can make 10-15 times more likely to develop bile duct cancer