Flashcards in GI cestodes and trematodes Deck (22):
What are the three basic structures of the tapeworm?
1. Scolex - attachment 2. Neck - new segment generation 3. Body (strobila) - a long segmented structure
What is the cause of beef tapeworm?
What is the transmission for beef tapeworm (taenia saginata)?
Ingestion of encysted larvae in undercooked beef
What is the diagnosis for taenia saginata?
Detection of proglottids or eggs in stool
What is the cause of pork tapeworm?
What is the transmission for pork tapeworm (taenia solium)?
Ingestion of cysts from undercooked pork
How does extra-intestinal disease (cysticercosis) result from pork tapeworm (taenia solium)?
Ingestion of embryonated eggs
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
What is the cause of fish tapeworm?
What is the transmission of fish tapeworm?
Ingestion of infectious larvae from undercooked fish
What are the symptoms of fish tapeworm (diphyllobothrium latum)?
1. Transient nausea 2. Abdominal pain 3. Diarrhea 4. Macrocytic anemia - B12 deficiency (rare)
What is the genus and species of dog tapeworm?
What are the properties of dog tapeworm infection?
1. Humans are intermediate host 2. Acquired through exposure to dog feces
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
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
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)
What is the diagnosis for fasciolopsis buski?
Detection of eggs in stool
What are the two liver flukes?
1. Fasciola hepatica 2. Clonorchis sinensis
Where is the liver fluke fasciola hepatica found?
Larval forms encyst on freshwater vegetation
Where is the liver fluke clonorchis sinensis found?
Larval forms encyst in fish
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)