Ascaris lumbricoides – Unfertilized Egg

Not infective to human Detected in faecal specimens of infected human Diagnostic Features Size: 90 µm x 40 µm. Range, 85-95 µm x 35-45 µm – larger than fertilised egg Shape: Elongated Colour: Brown Mammillated covering absent or less prominent Shell is often very thin Filled with an irregular mass of protoplasm

Ascaris lumbricoides – Fertilized Egg

Infective stage to human Detected in faecal specimens of infected human Eggs not infective when passed; need to develop in soil for a few weeks Diagnostic Features Size: 60 µm x 45 µm (range, 45-70 µm x 35-45 µm) Shape: Round or ovoid Colour: Brown due to bile staining Mammillated albuminous coat on outer shell […]

Enterobius vermicularis – Egg

Infective stage to human Detected mostly in perianal scraping of infected human Eggs partially embryonated when passed and become infective within a few hours; no development in soil Diagnostic Features Size: 55 µm x 26 µm (range: 50-60 µm 20-32 µm) Shape: Flattened on one side and other side convex Smooth, thin almost colourless transparent […]

Trichuris trichiura – Egg

Infective stage to human Found in faecal specimens of infected human Eggs not infective when passed; require development in soil for a few weeks Diagnostic Features Size: 54 µm x 22 µm (range: 49-65 µm x 20-29 µm) Shape: Lemon or barrel shaped Thick-shelled and yellow brown in colour Colourless opercular plugs at each end […]

Ancylostoma duodenale – Egg

Detected in faecal specimens of infected human Egg not infective to human Egg develops in soli and hatches into a rhabditiform larva and then to a filariform larva Diagnostic Features Size: 60 µm x 40 µm (range, 57-76 µm x 35-47 µm) Shape: Oval or ellipsoidal Shell is thin and colourless Contain 4 -8 cells

Trichomonas vaginalis – Trophozoite

Habitat in human: In female: lower genital tract; In males: urethra and prostate gland Detected in fresh vaginal secretions of infected female; urine sediment sample of infected male Diagnostic Features Size: 7-30mm in length Pear shaped Characteristic jerky movement when live Undulating membrane, bordered by a flagellum, extends half way along body 05 flagella: 4 […]

Giardia lamblia – Cyst

Cyst is the infective stage to human Detected in faeces of infected human Diagnostic Features Size: 11-12 mm (range: 8-19mm) in length Shape: Oval and small Up to 04 nuclei – at least 02 visible; usually located at one end Thread-like remains of flagella, remains of axonemes and parabasal bodies usually visible Cytoplasm often retracts […]

Giardia lamblia – Trophozoite

Habitat in human: Small intestine – duodenum and upper jejunum Detected in faeces of infected human Diagnostic Features Size: 12 – 15 µm (range 10 – 20 µm) in length Shape: Pear shaped and Bilaterally symmetrical Dorsal surface is convex and ventrally concave Sucking disc on ventral surface 02 nuclei 04 pairs of flagella Axostyle […]

Balantidium coli – Cyst

Cyst is the infective stage to human Detected in faeces of infected human Diagnostic Features Size: 50-55 µm (range 45-65 mm) Shape: Large, oval or round shaped Thick walled No cilia and is non motile Kidney shaped macronucleus Contractile vacuoles visible in the cytoplasm