Toxoplasma gondii Infection in the United States, 2011-2014

Area of Science:

• Medical Parasitology
• Public Health Epidemiology
• Immunology

Background:

• Toxoplasma gondii infections can lead to severe neurological and ocular diseases, particularly in congenitally infected infants and immunocompromised individuals.
• Understanding the seroprevalence and risk factors of Toxoplasma gondii is crucial for public health interventions and disease prevention strategies.

Purpose of the Study:

• To determine the seroprevalence of Toxoplasma gondii immunoglobulin (Ig) G and IgM antibodies in the US population.
• To identify demographic and socioeconomic risk factors associated with Toxoplasma gondii infection.

Main Methods:

• Analysis of serum samples from 13,507 participants aged ≥6 years in the National Health and Nutrition Examination Survey (2011-2014).
• Testing for Toxoplasma gondii IgG and IgM antibodies, with IgG avidity testing for dual-positive cases.
• Multivariable analysis to assess risk factors for seropositivity.

Main Results:

• Overall Toxoplasma gondii IgG seroprevalence was 11.14% (age-adjusted 10.42%).
• Risk factors for IgG seropositivity included older age, male sex, lower socioeconomic status, lower educational attainment, and non-Hispanic Black, Mexican American, and foreign-born non-Hispanic White individuals.
• Toxoplasma gondii IgM seroprevalence was 1.16%, with dual IgG/IgM positivity at 0.71%. Risk factors for dual positivity included older age, crowding, and non-US birth origin.

Conclusions:

• Toxoplasma gondii antibody prevalence in the US is relatively low but higher among non-US-born individuals, males, and certain minority and socioeconomically disadvantaged groups.
• Recent infections (IgM positive) are uncommon, and when present, are associated with specific risk factors.
• Findings highlight the importance of considering demographic and socioeconomic factors in Toxoplasma gondii epidemiology.