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

80 µm by 55 µm

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

Cycle repeated

Infection:

Paragonimiasis

Eating of raw/

improperly

cooked

crab/

caryfish

Drunken crab:

Strips

of raw

crab in

alcohol

(China)

Adolescaria

inside a cyst

Digestive tract

Lungs

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

Intradermal

test

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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