Parasitology
Lab-1 (E.coli)
Introduction :: ) (غير مهم
1- Classification of parasites
2- Diagnosis of parasite ( by stool examination , blood examination , x-ray ,…….)
3- General stool examination (GSE)----- if the test is positive that means there are
pathogenic parasites but when the test is negative that means there are non-
pathogenic parasites or food particles or waste products in the stool
4- Preparation of (GSE)----- (1)without iodine stain to see the motile trophozoite
(2) with iodine stain to see dead trophozoite but it use to see cyst and eggs
E.coli ) (المطلوب
1- non-pathogenic parasite
2- 10%-20% of population have E.coli without any symptoms
3- habitat : lumen of large intestine mainly in cecum
4- route of infection : feco-oral route
5- infective stage : cyst
6- diagnostic stage : tropozoite (-)+ cyst
7- morphology :
Trophozoite:
1- It has more granular endoplasm containing ingested bacteria and debris and food
particles (no RBCs) .
2. The ectoplasm is not clear. and it has short and wide pseudopodia.
3. It has one nucleus contain large eccentric karyosome, and large chromatin granules
arranged irregularly beneath nuclear membrane.
4- size: 10-50 microns
Mature Cyst:
1- small , spherical to oval in shape , containing 4-8 nuclei , usually found in feces
2- size: 10-30 microns
3- nuclear morphology of the cyst is similar to that of trophozoite but they are smaller
Immature Cyst:
1- containing 2-4 nuclei
2- chromatoid bodies
3- glycogen