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ABSTRACT: The northeastern highlands of Brazil are endemic for several tropical diseases, especially American trypanosomiasis (Chagas' disease) and schistosomiasis. Twenty years ago, we measured the seroprevalence of protozoan diseases in Santo Inácio, a village of approximately 1,000 inhabitants located 1,000 m above sea level. We detected small numbers of sera with antibodies against Trypanosoma cruzi and Toxoplasma gondii, and the area had a low prevalence both of American trypanosomiasis (3.54%) and toxoplasmosis (27.43%) compared with nearby Brazilian areas. This was attributed to a specific triatomine vector and local housing conditions. Twenty years later, we again determined the prevalences of both diseases and compared these results with those from Iraquara, a larger town with the same ethnic and social background but with a higher prevalence of rural activities. The incidence of Chagas' disease in San Inácio showed the same low level, i.e., 3.78% (5 of 132) with only adult males affected in contrast with Iraquara, which had an incidence of 34.5%, but a low prevalence of only one of 22 among children up to 14 years of age. Santo Inácio maintained a low (25.8%) seroprevalence for toxoplasmosis. Housewives presented a higher incidence of toxoplasmosis during both periods, probably due to related risk factors. Cats were found less frequently in Santo Inácio than in Iraquara, which showed an incidence of 65.5% seropositivity for Toxoplasma gondii. These results suggest that the environmental conditions of Santo Inácio were preserved after 20 years, with a low incidence of these selected protozoan diseases.
The American journal of tropical medicine and hygiene 12/1998; 59(5):736-40. · 2.59 Impact Factor
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ABSTRACT: The excreted/secreted antigens (ESA) of Toxoplasma gondii are thought to play an important role in the pathogenesis and immune escape of the parasite and the host's immunity to infection with it. In the present study, ESA from peritoneal exudates of infected mice were precipitated with ammonium sulphate (a 40% saturated solution giving the best yield of antigenic components). They were then analysed by immunoblot assay and dot-ELISA using serum samples from 25 patients with toxoplasmosis (19 in the acute phase and six chronic). Three groups of antigens, with molecular masses of 35, 30-32 and 26 kDa, reacted strongly with IgG antibodies, and antigens from two of these groups (30-32 and 26 kDa) also reacted with IgM and IgA.
Annals of Tropical Medicine and Parasitology 02/1998; 92(1):23-30. · 1.43 Impact Factor
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ABSTRACT: A solid phase method, thin-layer immunoassay (IgM-TIA) was standardized and evaluated for the immunodiagnosis of acute toxoplasmosis, through the detection of IgM antibodies to Toxoplasma gondii. A total of 300 serum samples from serologically defined acute toxoplasmosis and, from non-related infections, was investigated by IgM-TIA. Statistical analysis were carried out in comparison with conventional tests, the immunofluorescence test for the detection of IgM antibodies (IgM-IFI) and hemagglutination test which uses 2-mercaptoethanol serum treatment (2ME-HA). Also the correlation coefficients were calculated for various Toxoplasma gondii antigen concentrations, as well as, the influence of the antigenic concentration on the relative indices of sensitivity and specificity were verified. The intra and inter test reproducibilities were demonstrated statistically, as well as, the reutilization of T. gondii antigen was proven to be possible for at least 10 times. The data indicated that antigenic concentrations, from 70 to 100 Cmg/ml, were able to provide maximum sensitivity and specificity. IgM-TIA displayed similar diagnostic efficiency to those two conventional tests here utilized, and may be employed to make diagnosis of acute toxoplasmosis, mainly if laboratory animals are available.
Revista do Instituto de Medicina Tropical de São Paulo 32(1):51-7. · 1.00 Impact Factor
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ABSTRACT: With the purpose of studying immunosuppressant drug action on parasites, the effect of Cyclosporine and cortisone in experimental toxoplasma evaluation, a highly virulent strain of Toxoplasma gondii (RH strain) was used. The animals were divided in two groups: control and immunosuppressed. Two animals from each group were sacrificed daily. Evaluation was based on parasitemia and parasitism of peritoneal exsudate and presence of the parasite in heart, lung, liver, spleen, small bowel, brain, cerebellum, spinal cord and eyes. Parasite infestation in peritoneal exsudate was 10 times greater than parasitemia. Red spots were observed after the second day; after the fourth day, focal necrosis with softening and fluidification of brain tissue spattered throughout the nervous tissue with enhanced vascularization. Capillaries obstructed by Toxoplasmas gondii were found, causing infarction and necrosis due to toxic or enzymatic substances. Images suggestive of cells an "owl-eye", Cytomegalovirus-like were found, with T. gondii, both in the brain, as well as in the tear glands and small bowel. Blood stream parasite infestation was observed, no histopathological lesions were found in the remaining tissue, possibly due to lack of time, for all animals died within a week's observation. We conclude that immunosuppression has worsened the outcome, anticipating the disease in 24 hours.
Revista do Hospital das Clínicas 52(6):316-20.
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ABSTRACT: Toxoplasmosis is a highly prevalent zoonotic human infection caused by the Apicomplexa protozoon Toxoplasma gondii. The acute disease is usually mild or asymptomatic, except for foetal infection transmitted by acutely infected pregnant women, which courses as a devastating disease. In order to determine possible regional variations in risk factors, we studied the frequency of seronegativity in areas of the São Paulo Metropolitan Region, comparing titers and age groups. The prevalence of seronegativity was determined retrospectively in 1286 pregnant women receiving prenatal care at public health services in four selected areas of the São Paulo Metropolitan Region of similar socioeconomic background. The São Paulo City area had the higher frequency of seronegativity (41.1%), followed by the Northwest (31.5%) and Southwest (29.9%) areas, with similar intermediate levels, and by the Northeast (22.5%) area with the lowest frequency (p < 0.001). A rough estimate disclosed about 280 infected infants/year in the São Paulo Metropolitan Region. Serological titers analyzed by age group suggested a decline in antibody levels with age, as shown by a lower frequency of higher titers in older groups. Our study emphasizes the importance of determining the regional prevalence of toxoplasmosis for proper planning of public health prenatal care.
Revista do Instituto de Medicina Tropical de São Paulo 35(6):479-83. · 1.00 Impact Factor
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Revista do Instituto de Medicina Tropical de São Paulo 24(5):322-5. · 1.00 Impact Factor
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Revista do Instituto de Medicina Tropical de São Paulo 24(1):56-9. · 1.00 Impact Factor
