PARASITOLOGY Archives - LaboratoryTests.org https://laboratorytests.org/category/parasitology/ Everything About Laboratory Tests... Sat, 29 Jun 2019 09:10:53 +0000 en-US hourly 1 https://wordpress.org/?v=6.8.2 https://laboratorytests.org/wp-content/uploads/2018/11/cropped-Laboratory-Tests-32x32.png PARASITOLOGY Archives - LaboratoryTests.org https://laboratorytests.org/category/parasitology/ 32 32 Ascaris lumbricoides (Roundworm) Eggs: Morphology, Characteristics and Identification https://laboratorytests.org/ascaris-lumbricoides-roundworm-egg/ https://laboratorytests.org/ascaris-lumbricoides-roundworm-egg/#respond Tue, 26 Mar 2019 19:03:18 +0000 http://laboratorytests.org/?p=431 The Roundworm, Ascaris lumbricoides is the largest nematode parasite in human intestine. Disease caused by A. lumbricoides is called Ascariasis. Laboratory diagnosis of ascariasis can be made by demonstration of parasite (eggs, larvae or adult [...]

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]]> The Roundworm, Ascaris lumbricoides is the largest nematode parasite in human intestine. Disease caused by A. lumbricoides is called Ascariasis. Laboratory diagnosis of ascariasis can be made by demonstration of parasite (eggs, larvae or adult worm) or some serological methods on clinical specimens. Definitive diagnosis of ascariasis is made by the demonstration of eggs in feces.

A gravid female roundworm can lay upto 2,50,000 eggs per day. This accounts for about three eggs per mg of feces. At this concentration, the eggs can be readily seen by the microscopic examination of saline emulsion of feces. Two types of eggs are liberated from the female worm of Ascaris lumbricoides:

  • Fertilized eggs
  • Unfertilized eggs

Feces sample may show both fertilized and unfertilized eggs, or either type alone.Fertilized-and-Unfertilized-Eggs-of-Ascaris-Lumbricoides

Fertilized Eggs

The fertilized eggs are laid by females after inseminated by mating with a male. These are embryonated and develop into the infective eggs.

Morphology and Features

Shape Round to oval.
Size 50-70um x 40-50um
Covering Surrounded by a thick smooth transleucent shell consisting of three layers:
-The outer coarsely mamillated albuminoid coat
-A thick transparent middle layer
-Inner lipoidal vitelline membraneSome eggs are found in feces without the outer mamillated albuminous coat. These are called decorticated eggs.
Bile Staining Bile stained, golden brown in saline mount.
Floatation Floats in saturated salt solution.
Ovum Contains a large unsegmented ovum of granular mass with clear space at both the end.

Fertilized-Egg-of-Ascaris-lumbricoides

Roundworm-Egg
Fertilized-Egg-of-Ascaris-Lumbricoides

Unfertilized Eggs

The unfertilized eggs are laid by uninseminated female. Thes are non-embryonated and cannot become infective.

Morphology and Features

Shape Round to oval.
Size 90um x 45um
Covering Albuminous coat is thin, distorted and scanty.
Bile Staining Bile stained, golden brown in saline mount.
Floatation Doesn’t float in saturated salt solution.
Ovum Contains an unsegmented small atrophied ovum with a mass of disorganized highly refractile granules.

Unfertilized-Egg-of-Ascaris-lumbricoides
Unfertilized-Egg-of-Roundworm
Unfertilized-Egg-of-Ascaris-Lumbricoides


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]]> https://laboratorytests.org/ascaris-lumbricoides-roundworm-egg/feed/ 0 Differences Between Entamoeba histolytica and Entamoeba coli https://laboratorytests.org/differences-between-entamoeba-histolytica-and-entamoeba-coli/ https://laboratorytests.org/differences-between-entamoeba-histolytica-and-entamoeba-coli/#comments Tue, 06 Nov 2018 17:10:51 +0000 http://laboratorytests.org/?p=321 Genus Entamoeba includes a group of amoebic parasites. Among them Entamoeba histolytica is an important human pathogen causing amoebic dysentery as well as hepatic amoebiasis. Entamoeba coli is a commensal of large intestine, but doesn’t [...]

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]]> Genus Entamoeba includes a group of amoebic parasites. Among them Entamoeba histolytica is an important human pathogen causing amoebic dysentery as well as hepatic amoebiasis. Entamoeba coli is a commensal of large intestine, but doesn’t invade tissues.
Definitive diagnosis of amoebiasis depends on the demonstration of E. histolytica trophozoite or cyst in stool. Cases might get misdiagnosed because of similarities in their structure. Following are the structural differences between E. histolytica and E. coli.


S.N Characteristics Entamoeba histolytica Entamoeba coli

Trophozoite
1. Structure Entamoeba-histolytica-trophozoite Entamoeba-coli-trophozoite
2. Size 12-30 µm 20-40 µm
3. Motility Progressive.

Hyaline, fingerlike pseudopodia

 Sluggish, nondirectional

Granular pseudopodia
4. Nucleus 1, difficult to visualize in unstained smear 1, often visible in unstained smear
5. Karyosome Sharp central Eccenteric
6. Pheripheral Chromatin Fine and dispersed Coarse and Clumped
7. Cytoplasmic Inclusions RBCs, leukocytes and tissue debris but no bacteria Bacteria and other material but never RBCs

Cysts
1. Structure Entamoeba-histolytica-cyst Entamoeba-coli-cyst
2. Size 10-15 µm 15-25 µm
3. Shape Usually spherical Usually spherical, may be oval, triangular or other shaped
4. Nucleus Mature Cyst=4 nuclei Mature Cyst=8 Nuclei
5. Peripheral Chromatin Fine and dispersed Coarsely granular or clumped
6. Chromatoid Bodies Rounded ends Filamentous, thread like, pointed ends
7. Glycogen Mass Visible in uninucleate stage Large and visible in binucleate stage

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