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Giardiasis (view source)

Revision as of 17:42, 11 August 2010

88 bytes removed , 17:42, 11 August 2010

→‎Laboratory Tests

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===Laboratory Tests===

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~~Haematology~~, ~~biochemistry~~ and ~~urinalysis usually give results within normal limits~~.

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Diagnosis is confirmed by demonstrating ''[[Giardia]]'' antigen, trophozoites or cysts in the faeces. The simplest method is to stain a fresch faecal smear with Diff-Quik or Lugol's iodine to reveal trophozoites. ''[[Giardia]]'' trophozoites are approximately 8 x 15 microns in dimension, tear-drop shaped organisms and contain two nuclei. They can be seen to move in a "falling leaf" pattern in wet mounts. As cysts are relatively "heavy", cysts must be floatated in higher density solutions prior to visualisation. Suitable solutions include zinc sulphate solution and sugar flotation solution. Centrifugal flotation in zinc sulphate solution is preferred as cysts can be envisaged with minimal distortion. Cysts are around 12 microns long and, if not distorted, oval in shape. When looking for cysts, three samples collected at two to three day intervals should be examined as shedding is intermittent.

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Diagnosis is confirmed by demonstrating ''[[Giardia]]'' antigen, trophozoites or cysts in the faeces. The simplest method is to stain a fresch faecal smear with Diff-Quik or Lugol's iodine to reveal trophozoites. ''[[Giardia]]'' trophozoites are approximately 8 x 15 microns in dimension, tear-drop shaped organisms and contain two nuclei. They can be seen to move in a "falling leaf" pattern in wet mounts.

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Commercial ELISA tests are now available for the detection of ''[[Giardia]]'' antigen in faeces. These include the Snap ''[[Giardia]]'' test from IDEXX and the ProSpectT/Giardia ELISA from Alexon-Trend.

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As cysts are relatively "heavy", cysts must be floatated in higher density solutions prior to visualisation. Suitable solutions include zinc sulphate solution and sugar flotation solution. Centrifugal flotation in zinc sulphate solution is preferred as cysts can be envisaged with minimal distortion. Cysts are around 12 microns long and, if not distorted, oval in shape. When looking for cysts, three samples collected at two to three day intervals should be examined as shedding is intermittent.

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Commercial ELISA tests are now available for the detection of ''[[Giardia]]'' antigen in faeces. These include the Snap ''[[Giardia]]'' test from IDEXX and the ProSpectT/Giardia ELISA from Alexon-Trend.

===Endoscopy===

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