Topic 5 Post Midterm 1 Flashcards
(93 cards)
What are flatworms also known as?
Flukes (Trematodes)
Name the 4 features of flukes
- flat leaf shaped bodies
- suckers for attachment
- covered in cuticle for protection
- no segmentation
Where do flukes live?
Inside another organism (ex: inside an animal or human - may live in the intestine or circulatory system)
Name two components of the fluke
oral sucker and intestine
What is the other name for an asian liver fluke?
Clonorchis sinensis
How many hosts do flukes have?
2 intermediate hosts (primary and secondary)
What animals do the lifecycles of flukes contain?
- Snails
- Fish
- Humans
What is the lifecycle of flukes? (6)
- Embryonated eggs passed in feces (diagnostic stage)
- Eggs are ingested by the snail
- Free-swiming cercariae encyst in the skin or flesh of fresh water fish
- Metacercariae in flesh or skin of fresh water fish are ingested by human host (infective stage)
- Excyst in duodenum
- Adults in biliary duct
What is clonorchiasis?
Infection of Clonorchis
- live in the bile duct
- may not be a problem
- if you have quite a few they eat the bile and you can have digestive issues
What are S+S of clonorchiasis?
- Jaundice
- N/V
- Diarrhea
- Abdo pain
- Liver enlargement
What do liver flukes infect?
Ruminants (including goats, moose, sheep, etc)
What does the life cycle of a liver fluke include?
A snail and mammal (most of them) or a fish
Describe how the liver fluke is passed
- The goat eats the larvae with the grass
- The larvae grow into adult liver flukes that are found in the liver of the goat
- The adult liver fluke lays eggs which pass out in the dung
- A larva hatches from the egg
- The larva swins, infects a special type of snail and develops through various stages
- The final larval stage leaves the snail and swims
- The final larval stage attaches to grass or plants
What are human lung fluke missing?
Reproductive organs
What does the lifecycle of human lung fluke include?
- Snails
- Crustaceans
- Humans
What are the 8 steps of the human lung fluke lifecycle?
- Hermaphroditic adult fluke releases eggs into human lung
- Eggs reach water after being excreted in feces
- Miracidium develops in egg and hatches from egg
- Free-swimming miracidium enters snail
- Inside snail, miracidium develops into redia, which reproduces asexually to reproduce rediae; several cercaria develop within redia
- Cercaria leaves snail and enters crayfish
- In crayfish, cercaria encysts to produce metacercaria
- Infected crayfish is eaten by humans, and metacercaria develops into adult fluke
What is the definitive host in a human lung fluke?
Human
What is the intermediate host in the human lung fluke?
Crustaceans and snails
What is the other name for Blood fluke?
Schistosoma sp
What host is the human in a blood fluke?
The definitive host
Where are eggs shed in the blood fluke?
In feces and urine
What does the larval stage do in blood fluke?
It parasitizes aquatic snails
What blood vessel do blood flukes attach to?
Large blood vessels (ex: hepatic blood vessel)
- It sticks itself into that blood vessel and takes oxygen from blood and takes some blood too
What is the intermediate host in blood flukes?
Snail