Schistosoma japonicum
Assistanted Prof. Sheng
morphology
1. Adult :male and female
are different.
They always hug toghter.
：
Seven testis are line up
：
Ovary located in the middle
of the parasite
2. Egg
Small fin
3.miracidium
4. cercaria
Live cycle
adult
The mature egg passes
Out in the feces
Eggs are laid in the terminal capillary
Vessels in the intestinal wall
miracidium
egg
And it come into water
Human infected by
Contect the water the cercaria
Penetration the skin
Miracidium penetrates soft parts
Of snail host
Free-swimming cercaria
The worm migrans in small bloodvessel and
Lymphatic vessel to lung,at last it go through
The systemic circulation to the inferior mesenteric
adult
Young
worm
Pathogenesis and clinical manifestation
1. Free-swimming cercaria:
------skin inflammation: partly rash, itch
2. Young worm:
A. Young worm penetrate pulmonary capillaries--- cause sport bleed
B. Secretion and excretion are toxin:
the patient cough ,phlegm with blood ,fever ,urticarial ,
acidophilic cell rised etc.
3.adult:
V.internal membrane inflation
V.external membrane inflation
4.egg
1. Located area:
A. liver
B. colon wall :especially in the descending colon,
sigmoid colon ,rectum
C. lung and brain etc.
2. The pathogenesis
stimulate
egg
cause
secrete
SEA
stimulate
B cell
Ab
TC
Acidophilic cell
B cell come together
When abscess are absorbed
granulomatous
Ab-Ag
Lymphokine
Acidophilic abscess
casinical
Fibro-tissue
Schistosoma is parasite in the inferior
Mesenteric,why the egg is passed out
in the feces?
?
Acidophilic
abscess
Egg are local in the
intestinal wall
Abscess fall
Down into
the intestine
Inferior messenteric
Cirrhosis and ascites
?
Hepatic
portal
Superior
mesenteric
Inferior
mesenteric
3. Clinical symptom:
Acute and chronic stage:
When the abscess fall down into the intestine : the patient
feel abdomen pain ,diarrhea , blood stood.
When the egg locate in the liver: enlarging liver, spleen
become large.
Intestinal wall fibrosis
At last it lead to fibrosis
Liver cirrhosis
diagnosis
Look for egg--- sure diagnosis
Method:
1. Natural sedimentation,miracidium hatching method
2. Rectumscopy :
3. Immunologic examination: ID, COPT, IHA, ELISA,
IFAT
Epidemiology
It has reported in china ,Japan, Indonesia,Philippines
1.Infective souce: patient ,cow or rat etc.mammal animal
2. Spread way: A. egg is passes into the water,
B. intermediate host exit:
C. human contact with “water”
3. All people are easy to be infective
The factors which effect epidemiology:
1. Biological factor; snail exit
2. Natural factor : rain ,temperature , geography
environment ,water, soil ,plant.
3. Social factor: live level, culture,habit etc.
treatment
1. Control infective resource:
A. Treat patient,carrier, infectived cow
B.eliminate mouse:
2. Cut off spread way:
A. Use physical and chemical ways to eliminate
intermediate host
B. Do not let the egg which is in the feces into water
3. Prevent yourself
Other two kind of schistosome:
1. Trichobilharzia
2. orientobilharzia
Both of them cause people infected cercarial dermatitis
1. Their definitive hosts are animal (duck ,bird, cow etc.)
2. The animal feces pass into water,the egg become
cercarial (infective stage)
3. People are infected by contact with the “water”
Treatment:
1. Prevent the animal’s feces pass into water
2. Protect people himself:
Take boots, packing leg, give unction before labour
The cercarial dermatitis will cure itself.