Parasitology
Lab-18 (Schistosoma mansoni)
1
-
Schistosoma mansoni :
1- definitive host : man
2- intermediate host : snail biomphalaria
3- habitat : mesenteric veins of man
4- infective stage to man :bifurcated tail cercaria (present in water)
5- diagnostic stage to man : egg ( stool examination )
6- route of infection : skin penetration (head only enter, but tail stay out) - oral route
7- life cycle
غير هام
((adult in the mesenteric veins of man embryonated egg in small
venule embryonated egg pass into lumen of intestine , go out with stool
Miracardium haches from egg , penetrate snail in the snail mother sporocyst
daughter sporocyst cercaria cercaria leave snail into water cercaria penetrate skin
of man carried by blood to the heart lungs heart portal vessels immature
worm become mature worm migrate back to mesenteric veins repeat the cycle ))
((cercaria enter liver through the artery develop to adult leave the liver through
the vein go to intestine ))
8- morphology :
Adult :
1- Have separate sexes ( male and female )
2- Male ( oral suckers - ventral suckers - gynecophoric canal - 6-9 testes near the
ventral suckers )
3- Female ( ovary located anteriorly and it is pink in color ) in S.hematobium
ovary located posteriorly or in the middle
o S.hematobium female ovary
) قريبة من الجهة الغامقة ( بالنهاية
o S.mansoni female ovary
) قريبة من الجهة الفاتحة ( بالبداية
Egg :
1- Oval
2- Large
3- No operculum
4- Contain fully developed Miracardium
5- Have small , lateral spine
Miracardium:
1. Swim very rapid searching for snails
2. Covered by cilia
Cerearia :
1. Bifurcated tail
2. Has body
3. After penetration of skin , it will lose its tail
4. Could enter through mouth or skin
9 – Symptoms : pruritus - rashes - Cough &hemoptysis - fever - Eosinophilia - urticara
- diarrhea - dysentery - weight loss - hepatospleenomegaly - anemia - abdominal
discomfort
10 - Diagnosis :
stool examination ( see egg ----- do the test after exercise )
liver Biopsy
Clinical picture
Hatching test (examination of eggs for viability – also use to check the following
patients)
Serological diagnosis
Skin test
Sigmoidoscopy and biopsy
11 - Treatment : oxamniquine – Niridazole – Praziquantel