Abstract
Purpose: :
There are in France three main strains of Toxoplasma gondii (genotypes I, II and III). The most common ocular consequence of congenital toxoplasmosis is retinochoroiditis: ocular lesions have been reported in 80% of untreated, congenitally infected children. But no data were available in France and Europe on genotype of T. gondii, on the prevalence of the different strains and on their respective virulence. The purpose of this study was to investigate the genotype of strains and the outcome of babies born with congenital toxoplasmosis in a city university hospital in France.
Methods: :
From 1980 to 2007, every newborn presenting with congenital toxoplasmosis in our university hospital was prospectively refferred to the parasitology department. Date of birth, sex, time of congenital contamination, pre- and post-natal treatment were recorded. We thereafter designed a retrospective follow-up of all these children.Fetal infection was detected using serologic analysis and parasitologic investigations, such as mice inoculation and PCR from samples of amniotic fluid or placenta. For 43 newborns, genotyping of T. gondii strains was performedusing multilocus analysis, using 5 or 6 micro satelits.
Results: :
The median follow-up was 38.6 months (13-240 months). The median date of maternal contamination was 30 amenorrhae weeks. 22 children (28.2% of 78 infected) were treated in-utero upon detection of the maternal infection. 47 infected children underwent a post-natal treatment (66.1% of 71 alive new borns). We analyzed the genotype of T. gondii for 43 infected children (55%). 41 strains (95.3%) were identified as genotype II and 2 strains (4.7%) as genotype III. Among the 10 children with at least 1 retinochoroidal lesion, 5 strains were analyzed: 4 were genotype II (2 peripheral lesions, 1 macular, 1 peripapillar) and 1 was genotype III (1 macular lesion).
Conclusions: :
Genotype II is confirmed in this study to be the most common strain in France. Percentages of ophthalmological and non ophthalmological lesions accorded to the literature. No prognostic factor was identified for the occurrence or the seriousness of retinal lesions. But only a prospective study concerning the different strains of T. gondii could allow us to evaluate their pathogenicity, severity and prognosis.
Keywords: toxoplasmosis • retinochoroiditis • chorioretinitis