Difference of Toxoplasma gondii antibodies between Thai and Austrian pregnant women.
Toxoplasma gondii IgG and IgM antibodies were compared in pregnant women from Thailand and Austria, using the Sabin-Feldman dye test and ISAGA-IgM in the same laboratory. In Thai pregnant women, IgG antibody was present in 21.7% and titres were mostly low; all Thai women were negative for IgM antibody. Conversely, in Austrian pregnant women, IgG antibody was present in 30.0% with a high titre, and 19 (6.3%) cases were positive for IgM antibody. The seropositivity of T. gondii IgG antibody in Austrian women was significantly higher than in Thai women (P=0.02) and the titres were much higher. The data may be explained if Thai women become infected at a younger age than Austrian women and so are in the chronic stage of infection with the corresponding lack of IgM antibody during pregnancy, and/or differences in the virulence of T. gondii strains in different parts of the world.