Investigação sorológica e molecular de toxoplasma gondii em doadores de sangue

• Autor(a) principal: Nakashima, Fabiana
• Data de Publicação: 2015
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da FAMERP
• Texto Completo: http://bdtd.famerp.br/handle/tede/267
• topic: Toxoplasma; Toxoplasmosis; Molecular Diagnostic Techniques; Serology; Toxoplasma; Toxoplasmose; Técnicas de Diagnóstico Molecular; Sorologia; CIENCIAS DA SAUDE::8765449414823306929::600

Introduction: Toxoplasma gondii, which causes toxoplasmosis, is an intracellular protozoan that has several transmission routes, among them the transfusion. Objective: To investigate by serological and molecular methods the T. gondii infection in blood donors to assess the risk of transmission via transfusion. Methods: We selected 750 individuals able to donate blood. These individuals were submitted to an interview about their lifestyle habits and a collection of peripheral blood. The immunosorbent assay (ELISA) was used to investigate the presence of anti-T. gondii IgM and IgG classes, and the Nested PCR and qQPCR, the parasitaemia. Positive samples in the molecular methods were submitted for genotyping by the Multilocus Nested PCR RFLP method. Donors with positive molecular result and no positive serology were recalled to investigate seroconversion by ELISA and Indirect Immunofluorescence (IIF). In addition, recipients of blood components with molecular suspected parasitemia were screened. Of these, aliquots were separated from peripheral blood prior to transfusion and after transfusion (± 20 days), which were also analyzed by serological methods (ELISA and IIF) and molecular (PCR, qPCR Mulitplex nested PCR and RFLP). Results: Three hundred and fifty-seven (47.6%) donors had positive result and 393 (52.4%) showed no positive result for the presence of anti-T. gondii IgG class. Twenty-seven (3,6%) showed positive result for IgM and 723 (96.4%) non-reactive. The variables associated with infection by T. gondii were: advanced age (P < 0.0001), consumption of raw milk (P = 0.001), consumption of raw and underare beef and pork meat (P = 0.003), to reside in the countryside (P = 0.004), frequent presence of mechanical vectors in the residence (cockroach, mouse and fly P = 0.02; mice, P = 0.03), lower education (1st grade incomplete, P <0.0001 and 1st grade complete, P = 0.002) and low family income (P = 0.002). No sample was positive by qPCR, but 40 (11%) were positive by Nested PCR and positive serology. However, these samples did not show amplification when undergoing to genotyping. The four cases screened did not show positive results to molecular analysis and no recalled donor presented seroconversion. Conclusion: We concluded that the studied population of blood donors is exposed to various risk factors associated with infection by T. gondii, and it is likely that the high frequency of anti-T. gondii IgG class found in this study is related to this exposure. The results show that there is no molecular evidence of parasitaemia in the studied donors, thus the risk of transmission of this infection via blood transfusion is low or zero in this region. In addition, the failure of genotyping and the non-occurrence of seroconversion of reanalyzed donors suggest that the positivity found in some samples analyzed by Nested PCR, were related to false-positive results.