Lab 3

• Protozoa


  • Phylum: Sarcomastigophora
  • Subphylum: Mastigophora (Flagallata)
  • Class: Zooflagellata (Intestinal and genital flagellates)

  
• Example-1


  • Giardia lamblia
• Giardia lamblia

  • Cosmopolitan parasite, more prevalent in children than adults and more common in warm than cool climates
  • Pathogenic parasite that causes disease called Giardiasis, Lambliasis
  • Habitat is duodenum and upper part of jejunum of man

  
• Trophozoite


  • Bilaterally symmetrical, pear shaped with broad, rounded anterior end and a tapering posterior end
  • Dorsally convex and ventrally concave forming sucking discs
  • One pair of nuclei one on each side of the midline with central karyosome
  • One pair of axostyle, one pair of deeply staining curved bars (parabasal bodies)
  • Four pairs of flagella arise from blepharoplasts on the ventral side of the body (2 anterior, 2 posterior, 2 caudal and 2 ventral)
• Cyst


  • Oval in shape, the mature cyst contains 4 nuclei which may remain clustered at one end or lying in pairs at opposite ends
  • Shows the axostyle, remains of the flagella and margins of the sucking discs inside the cytoplasm
• Transmission


  Transmission occurs by viable cysts that are swallowed through contaminated food and drink
• Pathology


  • Not invades the tissues but feeds on the mucus secretions
  • In acute infection there is duodenal irritation with excess secretion of mucus and dehydration, accompanied by dull epigastric pain and chronic diarrhea with a steatorrheic type of stool (fatty or oily diarrhea) containing a large amount of mucus and fat but no blood

  
• Diagnosis


  1. Examination of stool by direct smear (General Stool Examination GSE) to recover trophozoites and/or cysts stages

  2. Duodenal aspiration
• Example-2


  • Trichomonas
• Trichomonas tenax


  Harmless commensal of the human mouth, living in the tarter around the teeth
• Trichomonas hominis


  Inhabits the caecum of man, this parasite not invade the intestinal mucosa

  
• Pathology


  • Prefers a medium slightly alkaline or somewhat more acid than that of the healthy vagina (pH of healthy vagina is 3.8 – 4.4)
  • During infection of vagina, the vaginal walls become injected and tender with hemorrhage sometimes
  • In advanced cases there are granular areas
  • Patients present signs of vaginal and cervical inflammation, complain of itching and burning and have profuse leukorrheic discharge (a whitish or yellowish discharge of mucus from the vagina)
• Diagnosis


  1. In female, the microscopic examination of sedimented urine, vaginal discharge and vaginal scrapings

  2. In male, microscopic examination of urine, prostatic secretions