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Medical Parasitology Lab. Concentration techniques. Flotation Method. Concentration Methods. Sedimentation method Modified Formal- Ether sedimentation technique Acid- Ether sedimentation technique Flotation method Saturated Salt Solution technique
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Medical Parasitology Lab. Concentrationtechniques Flotation Method
Concentration Methods • Sedimentation method • Modified Formal- Ether sedimentation technique • Acid- Ether sedimentation technique • Flotation method • Saturated Salt Solution technique • Sheather’s Sugar Centrifugal Flotation technique • Zinc Sulphate Centrifugal Flotation technique
Flotation technique • These method use the high specific gravity of a solution to float the lighter ova and cyst. They can be improved by centrifugation. • Advantage: • Easy to perform . • Disadvantage: • Delay in examination can result in distortion. • Larvae and some fluke eggs do not concentrate. • Frequent checking of specific gravity.
Flotation Methods Saturated salt solution
Materials and Method • Boil granular sodium chloride in excess in water to produce a saturated solution which when cooled has a specific gravity of 1.18 - 1.2. • Half fill a wide- mounted flat bottomed container with the saturated salt solution. • Emulsify 1gm of feces in the solution and strain it to remove the debris from the surface. • Pour the filtrate into meniscus and fill it to the top with saturated salt solution. • Lay a glass slide or large coverslip over the top, avoiding any bubbles being trapped. • Leave for 20 min before quickly inverting the slide. • Scan for ova using the 10x objectives.
Saturated Salt solution technique • Advantages: • It is cheap preparation using simple apparatus. • It concentrates nematode ova well. • Disadvantages: • It doesn’t concentrate cysts.
Flotation Methods Sheather’s sugar centrifugal flotation technique
Materials and Method • Sheather’s sugar solution: • Table sugar --------------------------------------500gm • Distilled water ---------------------------------- 320ml • Phenol crystal ( melt in hot water bath) ----- 6.5gm
Procedures • Soften 1gm of feces with water to a soft. • Strain the aqueous suspension through a wire sieve. • Mix 1 part aqueous suspension with 2 part of Sheather's sugar solution. • Pour into a centrifuge tube, centrifugation 1500 rpm for 10 minutes. • Pour the supernatant into a meniscus and add a sufficient solution to bring the meniscus to the top. • Place a coverslip and wait for 10 minutes. • Examine under microscope.
Sheather’s Sugar solution technique • Advantages: • Reveals most nematode eggs and protozoan cyst. • Disadvantages: • Flukes eggs and tape worm eggs are not demonstrate well. • Also most nematode larvae are not demonstrate well.
Intestinal Protozoa Balantidium coli
Balantidium coli • Is a parasitic species of ciliate protozoa that cause balantidiasis or Balantidium dysentery. • Balantidium coli has two developmental stages, a trophozoite stage and a cyst stage. • The cystis the infective stage measures about 50 to 70 µm in diameter, characterized by the presence of a large kidney-shaped macronucleus. • The trophozoite is oval with 2 nuclei and measures approximately 50 to 100 µm long and 40 to 70 µm wide.
Intestinal Protozoa Cryptosporidium parvum
Cryptosporidium parvum • Infect human and most mammals. • The infective stage is oocyst containing sporozoites measuring 5u in diameter. • The diagnostics stage is oocyst containing 4 sporozoites. • Diagnosis: • Detecting oocyst in stool. • Acid-fast stain.
Tissue Protozoa Toxoplasma gondii
Toxoplasma gondii • Habitat: reticulo-endothelial system, monocyte, and muscle fiber and cause toxoplasmosis. • Humans can acquire Toxoplasma gondii infection by ingestion cyst or sporylatedoocyst • Cyst: precipitated in flesh of cow. • Sporulated oocyst: cat feces. • Intermediate host: Human. • Definitive host: Cat. • The tachyzoites are crescent-shaped and measure about 5 µm in length. • Diagnostic stages: • Diagnosis also can be done by detection antibody IgG, IgM, IgE and IgA.
Urogenital Protozoa Trichomonas vaginalis
Trichomonas vaginalis • Is the most common cause of vaginitis, inhabit the urogenital system • There is no cyst stage but only have trophozoitestage. • The trophozoite measures about 15 x 10 µm. The trophozoite has a single nucleus and four flagella and undulating membrane. • Diagnosis: • Male: finding trophozoite in urethral prostatic discharge • Female: finding trophozoite in vaginal discharge.
