Overview
- Enzyme-linked immunosorbent assay now most commonly used, available for IgG, IgM, antigen and immune complexes.
- Other tests: indirect immunofluorescence, indirect hemagglutination, latex agglutination.
- Single positive titer only indicates exposure, not recent or active infection (may persist for years).
Uses
Alone
- To support diagnosis of clinical toxoplasmosis
: rising IgG titer in paired samples 3 weeks apart.
Result data
Normal (reference) values
- No absolute values, normal animals may have very high antibody titers.
Abnormal values
- High IgM titer suggests recent or active infection.
- Fourfold increase in IgG titer in acute and convalescent samples taken 3 weeks apart indicates recent infection.
- In combination with clinical signs probably indicates cause of disease .
Errors and Artifacts
False positives
- Auto-immune diseases, eg if rheumatoid factor or anti-nuclear antibody present (ELISA and latex agglutination only).
- High titers in healthy previously exposed animals.
- Early in disease.
- If overwhelming disease in immunocompromised hosts, eg neonates.
- Cross reaction.
Sources
Publications
Refereed papers
- Bresciani K D, Costa A J, Toniollo G H, Sabatini G A, Moraes F R, Paulillo A C & Ferraudo A S (1999) Experimental toxoplasmosis in pregnant bitches. Vet Parasitol 86 (2), 143-145.
- Tomas W B (1998) Inflammatory diseases of the central nervous system in dogs. Clin Tech Small Anim Pract 13 (3), 167-168.
- Stiles J, Prade R & Greene C (1996) Detection of Toxoplasma gondii in feline and canine biological samples by use of the polymerase chain reaction. Am J Vet Res 57 (3), 264-267.
- Wilson M et al(1990) Serologic aspects of toxoplasmosis. JAVMA 196 , 277.
