Paragonimus
westermani
Named by:
Kerbert
(1878)
Braun
(1899)
Oriental lung
fluke
Lung distome
Japan, Korea,
Formosa, China
India:
Bengal,
Assam,
South
India
Nepal,
Africa,
South
America
Adult worms:
lungs of man
Adult worm:
thick,
fleshy,
egg-
shaped
Anterior end: slightly
broader
than
posterior
end
8-12 X4-6 X 3-
5mm
Ventral
sucker:
near
about
body’s
middle
Excretory
vesicle:
large
extends
posterior
to anterior
Divides
body in
2 equal
halves
2-blind intestinal
caeca
Unbranched
extend to
caudal
region
Genital
apparatus:
(Trematodes)
Life
span:
6-7
years
Eggs:
golden
brown,
oval,
flattened
opercula
Unsegmented
ovum
with
yolk
cells
3-hosts
One
definitive
2
intermediate
Definitive
hosts:
Man &
domestic
animals
Usual
hosts
(Asia):
tiger,
leopard
reservoirs
Reservoirs
Intermediate
hosts
1st:
fresh
water
snail
(Melania)
2nd:
fresh
water
crayfish/
crab
Adult worms:
respiratory
tract
(definitive
hosts)
Eggs
in
sputum
few in
faeces
Miracidium in
water,
2-7
weeks
Miracidium
escapes
in
water,
swims
Searches
its
snail
host:
Melania
Transforms
inside
soft
tissue
of snail
Sporocyst, 1st,
2nd
rediae
cercariae
Whole cycle:
10-12 weeks
Cercariae
escape
from
snail in
water
Enter 2nd
intermediate host
A freshwater
crab/ crayfish
Become
encysted
(viscera,
muscles
gills)
Infection:
eating
of raw
flesh of
crab
Cyst
wall:
lost by
gastric
juice
Adolescaria:
in duodenum
Young worms:
small
intestine,
cavity of
abdomen
Later,
migrate
upwards,
pierce
diaphragm
2-layers
of pleura,
gain
entry
in lungs
Settle,
grow to
sexual
maturity,
2-weeks
Eggs:
coughed
with
sputum
Infection:
Paragonimiasis
Eating of raw/
improperly
cooked
crab/
caryfish
Drunken crab:
Strips
of raw
crab in
alcohol
(China)
Adolescaria
inside a cyst
Adult worm:
lesions
Eggs:
excite
a
foreign
body
Granulomatous
reaction
Soften to
form cavities
Pulmonary
paragonimiasis
chronic
cough,
haemoptysis
pulmonary TB
Extrapulmonary
paragonimiasis
parasite can
enter liver,
intestine,
peritoneum,
other organs
Clinical
manifestations
organs
involved
Abdominal
organs:
pain in
abdomen,
diarrhoea
liver
enlargement
Cerebral
infection:
jacksonian
type of
epilepsy
Brain
tumour
that
may
be
fatal
Symptoms:
fever,
lymphadenitis
cutaneous
ulceration
Eggs
(sputum)
when
Viewed
(microscope)
Eggs
also
found
in
stool
Chest X-ray:
Abnormal
shadows
Emetine
Choloroquine???
Biothionol
(Yokogawa &
De Jongh,
1961)
Disinfection:
Sputum,
faeces
Eradication:
molluscan host
Raw, freshly
salted/
Inadequately
cooked
crabs
crayfish
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