VI- GI Cestodes/Trematodes

Question 1

3 basic structures

cestodes

Answer 1

1. head/scolex - has hooks or suckers
2. neck - new body segments generated from
3. body/strobila - long semented structure of individual proglottids

Question 2

small intestines host

definitive host

Answer 2

1. taenia saginata/beef
2. taenia solium/pig
3. diphyllobothrium latum/fish

Question 3

intermediate host cestodes

Answer 3

1. echinococcus granulosus/dog
2. taenia solium/pig

larval stages present instead of adult

Question 4

taenia saginata transmission

Answer 4

aka beef tapeworm

-eggs passed in human stools from adult worms in intestine
-cattle eat eggs and encyst in muscle

Question 5

taenia sagintata appearance

Answer 5

4 suckers on scolex

Question 6

taenia saginata symptoms

Answer 6

usually asymp
-mild abdom pain
-feeling fullness
-no crazy diarrhea

Question 7

taenia solium transmission

Answer 7

aka pork tapeworm
-same cycle as saginata just pigs eat eggs from human stool instead of cows
-person eats pork and gets infected with adult, OR intermediate host from fecal oral eggs

Question 8

taenia solium presentations

Answer 8

1. intestinal: from ingestion of adults
2. extraintestinal: ingestion of eggs, more severe, can lead to neurocysticercosis, invade brain and eyes

Question 9

diphyllobothrium latum

Answer 9

aka fish tapeworm
-eggs into freshwater for fish to eat > humans eat undercooked

Question 10

fish tapeworm appearance

Answer 10

grooves
-largest known to infect men

Question 11

fish tapeworm symptoms

Answer 11

1. asymp or mild- transient nausea, abdom pain, diarrhea
2. if multi worms - intestinal obsruction, macrocytic anemia from B12 def

Question 12

echinococcus granulosus

Answer 12

aka dog tapeworm

-dogs have adult tapeworms in intestines then shed eggs in feces for sheep to ingest/shed
-humans can get ingest eggs accidentally

vets, herding,

Question 13

echinococcus granulosus presenttaion

Answer 13

1. larvae secrete hyaline membrane that fill to form hydatid cyst in liver, lung, brain, bone marrow
2. ruptured cysts induce anaphylatic resp

Question 14

treating cestodes and trematodes

Answer 14

1. praziquantel for intestinal infections
   -inc Ca permeability of worm tegument so inc immune detection
2. benzimidazole for extraintestinal

Question 15

trematodes/flukes

Answer 15

ingest aquatic vegetation/plants
-esp in Asia

Question 16

fasciolopsis buski transmission

Answer 16

-eggs passed in stool then get into water
-larval form enters snail
-new larval forms encyst on vegetation (water chesnuts)
-humans ingest

Question 17

intestinal fluke symptoms

Answer 17

-light infection with single worm, focal inflamm, intermittent diarrhea
-heavy infection of multi worms then continous diarrhea, hemorrhage, ulceration, abscess

Question 18

liver flukes

Answer 18

fasciola hepatica, opisthorchis/clonorchis sinensis

-larval encyst on vegetation (hepatica) or frshwater fish (opis) for humans to eat

Question 19

liver fluke symptoms

Answer 19

fasciola:hepatomegaly, eosinophila, jaundice

opisthorchis: light infections/asymp OR heavy with biliary obstruction, gall stones, hepatitis, bile duct cancer, esp in immigrants