Table 3.
Diagnostic testing for selected parasitic CNS infections.
| Variable | Malaria | Trypanosomiasis | Microsporidiasis | Leishmaniasis |
|---|---|---|---|---|
| Specimen | ||||
| Serum | Serological tests (ParaSight-F and Immunochromoto- graphic Malaria Plasmodium falciparum test) are available, but false positive tests are common | … | Spores are seen in serum samples only during massive dissemination | ELISA and immunofluorescence assay have low sensitivity, compared with PCR |
| CSF | … | WBC count 15 cells/μL and organisms detected; CSF trypanosomal IgM may be helpful in early stages of disease | Spores can rarely be detected | … |
| Stool | … | … | Light microscopy of fecal samples to identify spores | … |
| Urine | … | … | Asymptomatic shedding can be detected in urinary sediment up to 6 months before renal failure or dissemination ensues | … |
| Skin scraping | … | … | … | In cutaneous form |
| Gold standard for diagnosis | Detection of parasites on thick and thin blood smears with Giemsa staining | Detection of organisms in CSF samples; card aggglutination trypanosomiasis test | Transmission electron microscopy may be useful for identification of species, but light microscopy is adequate for diagnosis | Culture of a biopsy specimen is required for speciation |