A Comparative Study of The Diagnosis of Toxoplasma Gondii in Human Placenta by Traditional Method, Restriction Fragment Length Polymorphism, and The Immunohistochemistry Method

Introduction: Toxoplasma gondii is an animal source of great importance in veterinary and public health.
Objective: The aim of this study was to detect genotyping of T. gondii by PCR-RFLP and to detect infection in placental tissue by immunohistochemistry (IHC) and to determine whether there is a correlation between the results obtained by this method and those obtained by through the traditional Impression method.
Material and methods: A total of 100O samples of placenta were selected for women who had aborted in the first months of pregnancy. In the beginning, all samples were stained with Gimsa stains using the steps of the Impression method, in which 40 (40%) samples were diagnosed with Toxoplasma infection, and 60 (60%) samples were not infected with Toxoplasma. The GRA6 gene was then amplified using the PCR method for all 40 positive tissue samples. In addition, an MseI exonuclease (PCR-RFLP) was added to all PCR products resulting from the amplification of the gene.
Results: After performing PCR-RFLP, it was discovered that the number of samples belonging to type I is 19, 13 for type II, and 2 for type III. The percentages were 47.5%, 32.5%, and 5% for the 3 types, respectively. Only 4 unknown and 2 negative samples were recorded. As for using the tissue immunohistochemistry method, and after tissue cutting of the 40 samples and the use of DAB, the result was 38 samples infected with toxoplasma plasma, which constituted 95%, while 2 samples were not infected with a percentage of 5%.
Conclusion: Several techniques can be used, but the immunohistochemistry technique is considered as a confirmatory test to classify aborted women into T. gondii infected women and non T. gondii infected women, and that PCR -RFLB method enables the identification of the most important species of Toxoplasma widespread.