Toxoplasma gondii infection in the United States, 1999-2000.

Infection with Toxoplasma gondii can lead to congenital and acquired disease, resulting in loss of vision and neurologic illness. We tested sera collected in the National Health and Examination Survey (NHANES) from 1999-2000 for T. gondii-specific immunoglobulin G antibodies and compared these results with results from sera obtained in the NHANES III survey (1988-1994). NHANES collects data on a nationally representative sample of the U.S. civilian population. Of 4,234 persons 12-49 years of age in NHANES 1999-2000, 15.8= (age-adjusted, 95% confidence limits [CL] 13.5, 18.1) were antibody positive; among women (n = 2,221) 14.9= (age-adjusted, 95% CL 12.5, 17.4) were antibody positive. T. gondii antibody prevalence was higher among non-Hispanic black persons than among non-Hispanic white persons (age-adjusted prevalence 19.2% vs. 12.1%, p = 0.003) and increased with age. No statistically significant differences were found between T. gondii antibody prevalence in NHANES 1999-2000, and NHANES III. T. gondii antibody prevalence has remained stable over the past 10 years in the United States.