Visceral flukes - Clonorchis sinensis Flashcards
AKA
chinese/oriental liver fluke
reservoir hosts
cats, dogs, tigers, foxes, mink
1st intermediate host:
snail
2nd intermediate host:
freshwater fishes such as carp
Oral sucker vs acetabulum
oral sucker slightly larger
Male reproductive system consists of:
2 large branched testes
large seminal vesicle leading to the genital pore
Ovary is relatively ____ and ____
small
lobed
Adults live in ____ of _____ and produce up to ____ eggs/day.
bile ducts
vertebrates
4000
Suckers are
small and weakly developed
Eggs are ______ when passed, but hatching occurs only after ____________
partially embryonated
ingestion by a suitable snail
Miracidium travels to the
digestive gland in the snail and transforms into sporocysts in 4 hrs
Sporocysts produce ____ in ___ weeks; each ____ produces ______
redia
two
redia
5-50 cercariae
______ emerge from snail and infect ______
Cercariae
freshwater fish
In the 2nd intermeidate host, each cercaria ______ & ___________
sheds its tail
encysts as metacercaria
Definitive hosts (vertebrates, including humans) become infected when:
they eat raw or undercooked fish (incl. steamed or smoked fish)
Juveniles excyst in the ______ & migrates _________
duodenum
up the common bile duct
Adult flukes reside in ____________ and begin producing _____ in 1 month
small and medium sized biliary ducts
eggs
Entire life cycle can be completed in ____ under ideal conditions
3 months
Adult worms can live up to ______ in the human host
25 years
Disease caused by clonorchis infection
Clonorchiasis
Clonorchis __________; amount of damage is linked to ______.
erodes bile ducts
worm density
Mean intensity of infection in endemic areas is ______ flukes
20-200
light infections, symptomless
Presence of 1000s of adult worms results in
diarrhea
painful hepatomegaly
jaundice
Unlike ______, Clonorchis does not invade ______ & does not cause extensive _______
Fasciola
liver tissues
liver necrosis
Repeated infections may lead to carcinoma (cancer) of the bile ducts (adenocarcinoma)
carcinoma of the bile ducts (adenocarcinoma)
Diagnosis:
recovery of characteristic eggs in the feces
Treatment:
Praziquantel taken orally for 2 days
Prevention/control:
Treatment of feces before using as a fertilizer. Complete protection is achieved simply by cooking fish. However, its difficult to get millions of people to change centuries-old eating habits
This disease is common in countries where:
raw fish is considered a delicacy
Clonorchiasis has also been reported in ______ areas (______) by consumption of ______
non endemic
including U.S.
imported and undercooked meat (china town SF)
