Problem: Toxoplasmosis is a major cause of congenitally acquired infections causing high degree of morbidity and mortality in the newborns.
Methods of study: IgG avidity method was used to distinguish the recent and more than 4 months old infection in a prospective cohort study for the first time in India. One hundred and eighty pregnant women presented in their first 4 months of pregnancy were included in this study. Their sera were tested for anti-Toxoplasma gondii antibodies using direct agglutination test, immunoglobulin (Ig)G and IgM-enzyme-linked immunosorbent assay, IgM-immunosorbent agglutination assay and VIDAS-IgG avidity.
Results: Overall IgG seroprevalence rate of toxoplasmosis was 45%. Only seven women (3.3%) were found to have IgM antibodies and only two of these showed low IgG avidity indicating recent infection of <or=4 months duration. One woman aborted spontaneously at her fourth month of gestation. In remaining five women the recent infection could successfully be excluded by IgG avidity testing. All these women had uneventful pregnancy.
Conclusions: This study indicated that all IgM antibody positive pregnant must be tested for IgG avidity to rule out recent primary infection.