Diagnostic methods | Pros and cons |
Parasitological diagnosis | |
Oocysts are only found in cats and other felids! Therefore serological methods are of great importance. The parasite (cysts or trophozoites) may be found in tissue biopsies. Free tachyzoites may be found in bronchoalveolar lavage samples. | - Parasitological diagnosis not conclusive since there are many latent infections
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Molecular diagnosis | |
Nested PCR and recently also real-time PCR are used to detect Toxoplasma in cerebrospinal fluid or tissue samples | - Excellent sensitivity and specificity of molecular methods
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Antigen detection | |
Only few reports on the detection of circulating antigens during acute infection | |
Antibody detection | |
Serology is the traditional method to detect Toxoplasma infections. Specific IgM antibodies are the most frequently used serological marker for a recent infection. However, false-positive results and the persistence of IgM antibodies complicate the interpretation. As an alternative approach, the measurement of the avidity of IgG antibodies against T. gondii by the titration method in patients with detectable IgM antibodies can efficiently define the stage of infection. | - Many commercial tests with excellent sensitivities and specificities are available and highly standardized
- Delayed or impaired antibody production in immunocompromised patients
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