Although several Toxoplasma gondii genotyping studies have been performed in Brazil, studies of isolates from animals in the state of Minas Gerais are rare. The objective of this study was to conduct a genotypic characterization of T. gondii isolates obtained from dogs, free-range chickens, and humans in Minas Gerais and to verify whether the T. gondii genotypes circulating in domestic animals correspond to the genotypes detected in humans. Genetic variability was assessed by restricted fragment length polymorphism at 11 loci (SAG1, 5′+3′SAG2, SAG2 alt, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico). Twelve different genotypes were identified among the 24 isolates studied, including 8 previously identified genotypes and 4 new genotypes. The genetic relationship of the 24 T. gondii isolates, together with the genotypes previously described from 24 human newborns with congenital toxoplasmosis, revealed a high degree of similarity among the genotypes circulating in humans and animals in Minas Gerais. The most common genotypes among these species were BrII, BrIII, ToxoDB #108, and ToxoDB #206. Restricted fragment length polymorphism at the CS3 locus of these 48 isolates showed that the majority of isolates presented alleles I (50%) or II (27%). Isolates harboring allele III at the CS3 locus presented low virulence for mice, whereas those harboring alleles I or II presented higher virulence. These results confirm the utility of marker CS3 for predicting the virulence of Brazilian isolates of T. gondii in mice. No association was found between the allele type and clinical manifestations of human congenital toxoplasmosis. This is the first report of T. gondii genotyping that verifies the overlapping genotypes of T. gondii from humans and animals in the same geographic region of Brazil. Our results suggest that there is a common source of infection to the species studied, most likely oocysts contaminating the environment.
Objective: To report a rare case of congenital toxoplasmosis from an immunocompetent mother with chronic infection who had reactivation of ocular disease during pregnancy.
Description:The newborn was asymptomatic at birth and identified by neonatal screening (IgM anti-Toxoplasma gondii in dried blood) among other 190 infants with congenital toxoplasmosis during a 7-month period. His mother had had a non-treated episode of reactivation of toxoplasmic retinochoroiditis during pregnancy, with stable IgG titers and negative IgM results. Results of IgM and IgG in the newborn's serum, as well as IgG immunoblotting were positive and active retinochoroidal lesions were detected in his peripheral retina. The neonate was treated with sulfadiazine, pyrimethamine and folinic acid. At 14 months of life, the child remained asymptomatic, with regression of retinochoroidal lesions and persistence of IgG.
ResumoObjetivo: Apresentar um caso raro de toxoplasmose congênita de uma mãe imunocompetente com infecção crônica que teve reativação da doença ocular durante a gestação.Descrição: O recém-nascido estava assintomático no nascimento e foi identificado através de triagem neonatal (IgM anti-Toxoplasma gondii em sangue seco) entre outros 190 bebês com toxoplasmose congênita durante um período de 7 meses. Sua mãe tinha tido um episódio não tratado de reativação de retinocoroidite toxoplásmica durante a gestação, com títulos de IgG estáveis e resultados negativos para IgM. Os resultados de IgM e IgG no soro do recém-nascido e o teste de immunoblotting para IgG foram positivos, e detectou-se lesões retinocoroideanas ativas na periferia da retina. O recém-nascido foi tratado com sulfadiazina, pirimetamina e ácido folínico. Aos 14 meses de vida, a criança permanecia assintomática, com regressão das lesões retinocoroideanas e persistência de IgG.
Congenital toxoplasmosis from a chronically infected woman with reactivation of retinochoroiditis during pregnancy
IntroduçãoA toxoplasmose congênita resultante da reativação de infecção crônica em gestantes imunocompetentes é considerada rara. Os casos relatados têm sido relacionados a uma possível redução da resposta celular durante a gestação, o que pode interferir com o controle de parasitas e o curso clínico da infecção materna e, posteriormente, aumentar o risco de transmissão vertical [1][2][3] .O impacto da reinfecção sobre a ocorrência de toxoplasmose congênita humana também é desconhecido. Casos resultantes de reinfecção têm sido relatados 4 , com a detecção
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