Visceral fluke - Paragonimus westermani Flashcards
AKA
Oriental lung fluke
Tegument is densely covered with ___________
scale-like spines
Oral vs ventral suckers
similar size
Two ___________ testes are situated _______
irregularly lobed
posteriorly
_________ is _____ to the ___ testis and is connected via oviduct to the uterus
lobed ovary
anterior
right
a ______ that lies _____ to the left ____
tightly coiled rosette
anterior
testis
Eggs are ____ and have a rather ___________
ovoid
flattened operculum
Vitelline follicles are ______ and _______, lying parallel to caeca
extensive
extend bilaterally
Ventral sucker is located:
medially between the ovary & uterus
Adults live in
the lungs where cross fertilization occurs
____ containing _____ are coughed up and expelled with sputum
Eggs
zygotes
Other eggs may get trapped in:
the surrounding lung tissue and produce bronchial abscesses
some eggs may be _____ with ____, passed through the _____ and expelled with ____
swallowed
sputum
digestive system
feces
Once eggs reach water, embryos require ____ in water before ______.
> 2 wk
miracidium’s development is complete
Miracidium must encounter & enter a snail host within ____
24 hours
Inside the snail, ____ and _____ generations are produced in the ______, which in turn develop many _____
sporocyst
2 redial
digestive gland
cercariae
Cercariae have
spined and knoblike tails, and emerge from the snail after 3 months of initial infection.
Their tail is useless for swimming
After emergence, they ____ over rocks until they encounter suitable crustaceans ________.
crawl
freshwater crabs, crayfish
Using their _______, they penetrate the crustacean’s exoskeleton and encyst in the crustaceans, where they develop into _______
sharply pointed stylet
metacercariae
How humans get infected:
Eating undercooked crustaceans
worms excyst in the:
duodenum & remain there for few days before entering the coelom
Later they penetrate ___________, and enter _______ and develop to sexual maturity in 2-3 months
the diaphragm and pleura
bronchioles of the lungs
wandering juveniles may become lodged in:
other organs
brain, heart and skin, producing ectopic lesions
disease caused by paragonimus infection:
Paragonimiasis
It has ________, but most of the cases are confined to the _________
worldwide in distribution
Oriental countries
Adult worms inside lungs provoke______
inflammatory rx
Symptoms:
dry cough, chest pain, difficulty in breathing, fever, blood/brownish streaks (i.e., fluke eggs) in the sputum, coughing up blood (hemoptysis)
Diagnosis
difficult to distinguish from other pulmonary disorders such as pneumonia and tuberculosis
Infection of abdominal wall may produce:
pain, diarrhea, and bleeding
most reliable diagnostic tool
Eggs found in rust-colored sputum
In the brain, infection may produce
epilepsy (seizure), cerebral tumor, paralysis
Treatment
Praziquantel taken orally over 3 days
Prevention
Cooking usually kill cysts in crustaceans and care should be taken with cysts on hands, knives and chopping boards
Control
Natural reservoir hosts include several crustacean-consuming carnivores; their population should be carefully monitored
