Abstract

Toxoplasmosis and mental retardation: report of a case-control study

Waleska T. Caiaffa¹

Clea A. Chiari²

Ana R. P. Figueiredo³

Fernando Orefice³

Carlos M. F. Antunes²

Fundação Ezequiel Dias, Centro de Pesquisa e Desenvolvimento, Belo Horizonte, Brasil

Universidade Federal de Minas Gerais, Instituto de Ciências Biológicas, Departamento de Parasitologia, Belo Horizonte, Brasil

Universidade Federal de Minas Gerais, Faculdade de Medicina, Serviço de Uveítes, Belo Horizonte, Brasil

A case-control study evaluating the association between mental retardation and toxoplasmosis was conducted among 845 school children in Belo Horizonte, MG, Brazil. Cases (450) were mentally retarded children attending a public school for special education. Controls (395) were children from the regular public school system. Clinical and anthropometric examinations and interviews were carried out to determine risk factors for toxoplasmosis and mental retardation. Diagnosis of Toxoplasma gondii infection was based upon an indirect immunofluorescent test (IFA); 55% of cases and 29% of controls were positive. The Relative Odds of mental retardation in children with positive serology was 3.0 (95% CI 2.2-4.0). Maternal exposure to cats and contact with soil were associated with an increased risk of mental retardation. Retinochoroiditis was fourfold more prevalent among cases than controls and was only diagnosed in T. gondii IFA positive participants. Congenital toxoplasmosis, in its subclinical form, appears to be an important component in the etiology of mental retardation, especially in high risk (lower socio-economic) groups. The population attributable risk was estimated as 6.0 - 9.0%, suggesting the amount of mental retardation associated with this infection.

Full text available only in PDF format.

Texto completo disponível apenas em PDF.

Publication Dates