parasitoloy

• General Stool Examination (GSE)


  A series of tests done on a stool sample to help diagnose certain conditions affecting the digestive tract, such as infection (from Parasites, Viruses, or Bacteria), poor nutrient absorption, or cancer
• Collection of Specimens


  1. Collect stool into a clean, dry container and deliver the specimen to the lab immediately

  2. Label the container with name patient, date of birth and the date

  3. Specimens must not be contaminated with water or urine

  4. Patient must leave the treatment for 72 hours before analysis
• General Stool Examination


  • Chemical Examination
  • Physical Examination
  • Microscopic Examination
• pH


  Normal: 7.0 - 7.5

  Abnormal: High pH may mean inflammation, cancer, or antibiotic use. Low pH may be caused by poor absorption of carbohydrate or fat.
• Physical Examination - Blood


  • Flashing blood: Injury in the last part of digestive system or hemorrhoids

  Lytic blood: Mixed with the specimen, may mean dysentery (bacterial or parasitic)
• Physical Examination - Mucus


  • Normal: No mucus

  Abnormal: Small amount may refer to infection in small intestine, Large amount not well mixed with stool may indicate lesion in large intestine by Giardia lamblia, Large amount, mixed with stool + blood streak = amoebic dysentery, Mucus + blood + pus = ulcerative colitis and bacillary dysentery
• Microscopic Examination


  1. Direct smear (Wet Mount Procedure)

  2. Concentration techniques (Sedimentation, Floatation)
• Entamoeba coli


  • Trophozoite
  • Cyst
• Ascaris lumbricoides


  • Ova
• Taenia spp.


  • Ova
• Trichuris trichura


  • Ova
• Hook worm


  • Ova
• Bacteria


  • In stool
• Pus


  • In stool
• RBCs


  • In stool
• Protozoa


  • Phylum: Sarcomastigophora
  • Subphylum: Sarcodina
  • Class: Lobosea
• Entamoeba histolytica


  • Entamoeba coli
• Entamoeba histolytica


  • Pathogenic parasite
  • Causes amoebic dysentery, amoebiasis, amebic liver abscess
  • Habitat is mucosa and submucosa of large intestine of man
  • Stages: trophozoite, precyst, cyst
• Trophozoite


  • Present in tissues only
  • Cytoplasm divided into clear outer ectoplasm and inner finely granular endoplasm
  • Motile with long finger-like pseudopodial extensions
  • Nucleus is spherical with deeply staining centric karyosome
• Precyst


  • Oval shape, smaller than trophozoite but larger than cyst
  • Blunt pseudopodium projecting from periphery
  • Food vacuoles disappear, no change in nucleus
• Cyst


  • Spherical shape with thick chitinous wall
  • Starts as uninucleate, then binucleate, quadrinucleate, and mature 8-nucleate cyst
  • Uninucleate and binucleate contain glycogen vacuole and chromatoid bodies
• • Food or drink contaminated with stool containing cysts is a common source of infection
  • Use of human excreta for fertilization of vegetables is an important source of infection
• Pathology of Entamoeba histolytica


  • Early lesion is tiny area of necrosis in superficial mucosa or small nodular elevation
  • Downward extension of ulcerative process to deep layers of intestine leads to large areas of necrosis

  
• Diagnosis is by examination of stool by direct smear (GSE) to recover trophozoites and/or cysts
• Entamoeba coli


  • Non-pathogenic parasite
  • Lives freely in lumen of large intestine of man
  • Stages: trophozoite, precyst, cyst
• Trophozoite of Entamoeba coli


  • Colorless
  • Ectoplasm difficult to distinguish from granular and vacuolated endoplasm
  • Round nucleus with thick membrane, irregularly distributed coarse chromatin, and large eccentric karyosome
  • Short, blunt, and granular pseudopodia
  • Numerous food vacuoles containing bacteria
• Cyst of Entamoeba coli


  • Spherical
  • Starts as uninucleate, then binucleate, quadrinucleate, and mature 8-nucleate cyst
  • Uninucleate, binucleate, and quadrinucleate contain glycogen vacuole and sharp-ended chromatoid bodies
• Diagnosis of Entamoeba coli is by examination of stool by direct smear (GSE) to recover trophozoites and/or cysts
• Protozoa


  • Phylum: Sarcomastigophora
  • Subphylum: Sarcodina
  • Class: Lobosea
• Entamoeba histolytica


  • Entamoeba coli
• Entamoeba histolytica


  • Pathogenic parasite
  • Causes amoebic dysentery, amoebiasis, amebic liver abscess
  • Habitat is mucosa and submucosa of large intestine of man
  • Stages: trophozoite, precyst, cyst
• Trophozoite


  • Present in tissues only
  • Cytoplasm divided into clear outer ectoplasm and inner finely granular endoplasm
  • Motile with long finger-like pseudopodial extensions
  • Nucleus is spherical with deeply staining centric karyosome
• Precyst


  • Oval shape, smaller than trophozoite but larger than cyst
  • Blunt pseudopodium projecting from periphery
  • Food vacuoles disappear, no change in nucleus
• Cyst


  • Spherical shape with thick chitinous wall
  • Starts as uninucleate, then binucleate, quadrinucleate, and mature 8-nucleate cyst
  • Uninucleate and binucleate contain glycogen vacuole and chromatoid bodies
• • Food or drink contaminated with stool containing cysts is a common source of infection
  • Use of human excreta for fertilization of vegetables is an important source of infection
• Pathology of Entamoeba histolytica


  • Early lesion is tiny area of necrosis in superficial mucosa or small nodular elevation
  • Downward extension of ulcerative process to deep layers of intestine leads to large areas of necrosis

  
• Diagnosis is by examination of stool by direct smear (GSE) to recover trophozoites and/or cysts
• Entamoeba coli


  • Non-pathogenic parasite
  • Lives freely in lumen of large intestine of man
  • Stages: trophozoite, precyst, cyst
• Trophozoite of Entamoeba coli


  • Colorless
  • Ectoplasm difficult to distinguish from granular and vacuolated endoplasm
  • Round nucleus with thick membrane, irregularly distributed coarse chromatin, and large eccentric karyosome
  • Short, blunt, and granular pseudopodia
  • Numerous food vacuoles containing bacteria
• Cyst of Entamoeba coli


  • Spherical
  • Starts as uninucleate, then binucleate, quadrinucleate, and mature 8-nucleate cyst
  • Uninucleate, binucleate, and quadrinucleate contain glycogen vacuole and sharp-ended chromatoid bodies