Association between seropositivity for Toxoplasma gondii, scholastic development of children and risk factors for T. gondii infection.

BACKGROUND: We evaluated the possible association of seropositivity for Toxoplasma gondii and certain risk factors for T. gondii infection with the scholastic development of children. METHOD: One hundred children aged 6-13 years attending the Hospital Municipal de Maringá Paranáa, Brazil, participated in the study. Serologic tests for IgG and IgM anti-T. gondii (indirect immunofluorescence (capture ELISA) were performed. The Scholastic Performance Test (SPT) for writing, mathematics and reading was applied to each child, and the result was classified as high, average or poor. The guardian of each child responded to a questionnaire about certain aspects of the child's living situation and diet. RESULTS: The prevalence of seropositivity for T. gondii was 8%. An association between seropositivity for T. gondii and scholastic development in the mathematics subtest and also consumption of fresh cheese were observed. Children with exposed soil, sand or grass lawn in their peridomicile were 9.116 times more likely to be infected by T. gondii. CONCLUSION: The findings showed the need to test school-age children for this parasite, educate families with T. gondii-positive children, provide training to educators, monitor recreation areas, and raise awareness of the need for care in handling food.

In vivo susceptibility to benznidazole of Trypanosoma cruzi strains from the western Brazilian Amazon.

OBJECTIVE: To assess the susceptibility of Trypanosoma cruzi strains from Amazon to benznidazole. METHODS: We studied 23 strains of T. cruzi obtained from humans in the acute phase of Chagas disease, triatomines and marsupials in the state of Amazonas and from chronic patients and triatomines in the state of Paraná, Brazil. The strains were classified as TcI (6), TcII (4) and TcIV (13). For each strain, 20 Swiss mice were inoculated: 10 were treated orally with benznidazole 100 mg/kg/day (TBZ group) for 20 consecutive days and 10 comprised the untreated control group (NT). Fresh blood examination, haemoculture (HC), PCR, and ELISA were used to monitor the cure. RESULTS: The overall cure rate was 60.5% (109/180 mice) and varied widely among strains. The strains were classified as resistant, partially resistant or susceptible to benznidazole, irrespective of discrete typing units (DTUs), geographical origin or host. However, the TcI strains from Amazonas were significantly (P = 0.028) more sensitive to benznidazole than the TcI strains from Paraná. The number of parasitological, molecular and serological parameters that were significantly reduced by benznidazole treatment also varied among the DTUs; the TBZ group of mice inoculated with TcIV strains showed more reductions (8/9) than those with TcI and TcII strains. CONCLUSIONS: Benznidazole resistance was observed among natural populations of the parasite in the Amazon, even in those never exposed to the drug.