Sedimentation in parasitological coproscopy

A sedimentation technique is described, in which a fecal suspension is placed on top of an aqueous sucrose solution of specific gravity 1.015 g/cm³. Using 100 by 15 mm test tubes, duplicate gravity sedimentation experiments were made using homogenized fecal suspensions (single-columns) and fecal suspensions placed on top of clear columns (double-columns). Egg- and cyst-counts, and turbidity determinations were made in the sediments obtained after definite time intervals. Most Ascaris lumbricoides, Trichuris trichiura and Ancylostomidae eggs sedimented within 20 minutes in single - and between 30 and 60 minutes in double-columns. Giardia duodenalis cysts required longer periods to sediment in double - than in single-columns; after 180 minutes (the maximum period of observation), double-column sediments produced 60.0% of the counts of single-columns. Double-column sediments were consistently less turbid than single-column ones

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Bibliographic Details
Main Authors: Moitinho,Maria da Luz Ribeiro, Ferreira,Cláudio Santos
Format: Digital revista
Language:English
Published: Instituto de Medicina Tropical de São Paulo 1992
Online Access:http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0036-46651992000300013
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Description
Summary:A sedimentation technique is described, in which a fecal suspension is placed on top of an aqueous sucrose solution of specific gravity 1.015 g/cm³. Using 100 by 15 mm test tubes, duplicate gravity sedimentation experiments were made using homogenized fecal suspensions (single-columns) and fecal suspensions placed on top of clear columns (double-columns). Egg- and cyst-counts, and turbidity determinations were made in the sediments obtained after definite time intervals. Most Ascaris lumbricoides, Trichuris trichiura and Ancylostomidae eggs sedimented within 20 minutes in single - and between 30 and 60 minutes in double-columns. Giardia duodenalis cysts required longer periods to sediment in double - than in single-columns; after 180 minutes (the maximum period of observation), double-column sediments produced 60.0% of the counts of single-columns. Double-column sediments were consistently less turbid than single-column ones