The Laboratory Diagnosis in Toxoplasma Infection

Abstract

The diagnosis of toxoplasmosis is of great importance due to the damage caused by this parasite in immunosuppressed people or in pregnant women, the diagnosis of an active toxoplasmosis represents a sign to initiate a pharmacological treatment immediately. The diagnosis of Toxoplasma can be performed with direct methods through intraperitoneal inoculation of serum or cerebrospinal luid, in susceptible mice evaluating the survival and detection of tachyzoites of biological samples. Indirect methods detecting the IgM and IgG isotypes against Toxoplasma have been the tools mostly used and had leaded to discriminate between an active and acute, from a chronic toxoplasmosis. Molecular methods actually Toxoplasma-DNA identiication by molecular biology tests like the polymerase chain reaction (PCR) allow the direct detection of the parasite. Polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLPs) have been used to identify three strain linages (type I, II and III). Recently, a high-resolution melting method was described to determine the genotype of the infection by Toxoplasma gondii directly from biological samples.

PCR Detection of Toxoplasma gondii in European Wild Rabbit (Oryctolagus cuniculus) from Portugal

“…However, to improve the sensitivity of the method, we used the SAG2 gene, since we previously had better results with this gene [23]. The PCR results, when we used the SAG2 gene, showed a sensitivity of 87.5% [29] and a specificity of 100% [30].…”

Toxoplasma gondii Infections in Animals and Humans in Southern Africa: A Systematic Review and Meta-Analysis

“…Immunodiagnostic methods include the Sabin-Feldman dye test (SFT), hemagglutination assay, immunofluorescent assay (IFA), modified agglutination test (MAT), avidity, western blot, enzyme-linked immunosorbent assay (ELISA), recombinant antigens, immunocytochemistry, and immunohistochemistry. Molecular techniques include Polymerase Chain Reaction (PCR), real-time PCR, PCR-restriction fragment length polymorphisms (PCR-RFLP), loop-mediated isothermal amplification (LAMP), and high-resolution melting (HRM) [21].…”

Immunodiagnosis and molecular validation of Toxoplasma gondii‐recombinant dense granular (GRA) 5 protein for the detection of toxoplasmosis in hemodialysis patients

“…Diagnostic approaches for detection of Toxoplasmosis include: serological assays, a variety of biological and molecular methods and histological and microscopic examinations but the specificity of diagnostic methods are not sufficient enough 1 . Also, microscopic and histological techniques have some technical errors in morphological detection like morphological similarity of diverse parasites in the same hosts, various microscopic forms of the same parasite in the different hosts, inappropriate staining, and incorrect recognition of tissue cyst from host 7–9 . Thus, the serological tests such as enzyme‐linked immunosorbent assay (ELISA), is the most common method of toxoplasmosis diagnosis in the world.…”