Seroprevalence and national distribution of human toxoplasmosis in Mexico: analysis of the 2000 and 2006 National Health Surveys

Abstract

Global warming has had serious implications on dispersion of infectious diseases like toxoplasmosis. Since the frequency of Toxoplasma gondii largely depends on climatic conditions, we studied its prevalence by means of 3599 samples of the National Health Survey 2000 (NHS-2000) and 2916 of the National Health and Nutrition Survey 2006 (NHNS-2006) serum banks, obtained from 1-98 year old subjects of both genders and all states of Mexico. Anti-T.gondii IgG antibodies were determined by ELISA and confirmed by western blot. Crude, epidemiologically weighted and diagnosis-performance-adjusted prevalence values were calculated. Seroprevalence changes were compared between both surveys and among regions (north, center and coast). Also, correlations between changes in temperature or humidity and those in prevalence were measured. National crude prevalence was 60.1% and 62.6% for NHS-2000 and NHNS-2006, respectively. Weighted and adjusted values were 62.5% and 40.0% for NHS-2000, and 63.7 and 43.1% for NHNS-2006. Coastal states and children presented the largest increases between surveys, while the center of the country showed a decrease. An apparently higher prevalence of T. gondii infection was observed in both surveys compared to that performed in 1987, while a geographical re-distribution was found from 2000 to 2006, with a positive correlation between temperature and frequency deltas in 21 states where prevalence increased.

Toxoplasma gondii Seroprevalence in the United States 2009–2010 and Comparison with the Past Two Decades

“…There was not a large enough sample of non-U.S. born persons to evaluate trends in this group. In many countries outside the United States, a relatively high percentage of persons are infected at an early age, 14,15 and therefore are already infected when immigrating to the United States. To examine trends in T. gondii seroprevalence over time, age-adjusted estimates from NHANES 2009-2010 among all persons and U.S. born persons 12-49 years of age (the age group in which serum was tested in all three NHANES surveys), and among childbearing age women (15-44 years of age), were compared with estimates from NHANES 1999-2004 and NHANES III (1988)(1989)(1990)(1991)(1992)(1993)(1994).…”

“…It may be that U.S. born Mexican Americans cook meat more thoroughly, have a lower exposure to cats in their environment, live in environments where oocysts do not survive as well in soil (for example, dry climates), or have hygiene practices that make them less likely to be exposed to T. gondii. Foreign born Mexican Americans have a higher T. gondii seroprevalence, 15 which generally reflects the T. gondii exposure risk of their region of origin.…”

Diagnosis, Treatment, and Prevention of Congenital Toxoplasmosis in the United States

“…T gondii seroprevalence rates vary in different parts of the world 84 and can range from <10% in some northern European countries 85 to as high as 60% to 80% (eg, in Mexico 86 and Brazil 87,88 ).…”

Diagnostic-test evaluation of immunoassays for anti-Toxoplasma gondii IgG antibodies in a random sample of Mexican population

“…Intra assay, inter assay and inter technician variation coefficients were 1%, 5% and 11%, respectively. Heterogeneous 14-113 kDa band patterns were obtained in western blot, with an antigen of around 35 kDa being the strongest and more frequently recognized, followed by three bands larger than 78 Recently, we reported the seroprevalence of human toxoplasmosis in Mexico using the ELISA IN sensitivity and specificity [26]. In the present study adjusted prevalence by Rogan-Gladen estimator was recalculated with the ELISA OUT and no significant variations were observed neither in the 2000 nor in the 2006 surveys (Table 3) [25].…”