Changes

===Laboratory Tests===

===Laboratory Tests===

Demonstration of ''Toxoplasma gondii'' in the tissues with associated inflammation is required for the definitive diagnosis of clinical toxoplasmosis. For example, tachyzoites may be seen in blood, cerebrospinal fluid, peritoneal and pleural effusions, aqueous humour or transtracheal washes from clinically ill animals. ''Toxoplasma gondii'' may also be detected in these samples using PCR, tissue culture or animal inoculation techniques¹. These methods may be employed on tissue biopsies too, as well as examination under haematoxylin and eosin or immunohistochemical staining. Immunohistochemistry is preferred to H&E because it is specific for ''T. gondii''. Demonstration of the organism is often most easily achieved post-mortem, as the size of the sample is not restrictive to the likelyhood of seeing ''T.gondii''. Even then, the pathogenesis of disease may be primarily immune-mediated in some cases and so there may be relatively few organisms to find. This is particularly true of opthalmic disease.

Demonstration of ''Toxoplasma gondii'' in the tissues with associated inflammation is required for the definitive diagnosis of clinical toxoplasmosis. For example, tachyzoites may be seen in blood, cerebrospinal fluid, peritoneal and pleural effusions, aqueous humour or transtracheal washes from clinically ill animals. ''Toxoplasma gondii'' may also be detected in these samples using PCR, tissue culture or animal inoculation techniques¹. These methods may be employed on tissue biopsies too, as well as examination under haematoxylin and eosin or immunohistochemical staining. Immunohistochemistry is preferred to H&E because it is specific for ''T. gondii''. Demonstration of the organism is often most easily achieved post-mortem, as the size of the sample is not restrictive to the likelyhood of seeing ''T.gondii''. In the absence of demonstration of ''Toxoplasma gondii'' in the tissues or fluids ante-mortem, there is no one specific test to diagnose toxoplamosis. However, a combination of various diagnostic procedures can be used to build a presumptive diagnosis.

In the absence of demonstration of ''Toxoplasma gondii'' in the tissues or fluids, there is no one specific test to diagnose toxoplamosis. However, a combination of various diagnostic procedures can be used to build a presumptive diagnosis.

Firstly, clinical signs should be suggestive of toxoplasmosis, despite variation in the presentation of disease between individuals. Although no pathognomic changes for toxoplasmosis are seen on routine haematology, biochemistry and urinalysis, certain results results are often seen in ''T. gondii'' infection. For example, most cats show a mild non-regenerative anaemia, and 50% of pateients are initially leukopenic due to lymphopenia. Neutropenia may occur in conjunction with lymphopenia, and leukocytosis may occur during recovery³. Most patients also show and increase in creatine kinase, ALT, SAP, and hypoalbuminaemia is also common^{1, 3}. 25% of cats show hyperbilirubinemia and icterus, and pancreatitis may cause low to low normal serum calcium. A mild proteinuria and bilirubinuria are often revealed by urinalysis.

 

 

* Clinical signs of disease referable to toxoplasmosis;

Routine haematology, biochemistry and urinalysis show no changes specific for toxoplasmosis. However, during ''T. gondii'' infection, several features may be seen and could be suggestive. For haematology, these might include: non-regenerative anaemia, neutrophilic leucocytosis, lymphocytosis, monocytosis, neutropenia or eosinophilia. Biochemical profiles could show increased creatine kinase, ALT, SAP, bilirubin and total protein, and proteinuria and bilirubinuria may be revealed by urinalysis¹.

* Demonstration of antibodies in serum, aqueous

* Demonstration of antibodies in serum, aqueous