A survey of congenital Chagas’ disease, carried out at three Health Institutions in São Paulo City, Brazil

The congenital transmission of Chagas’ disease was evaluated in 57 pregnant women with Chagas’ disease and their 58 offspring. The patients were selected from three Health Institutions in São Paulo City. The maternal clinical forms of Chagas’ disease were: indeterminate (47.4%), cardiac (43.8%) and digestive (8.8%); 55 were born in endemic areas and two in São Paulo City. The transmission of Chagas’ disease at fetal level was confirmed in three (5.17%) of the 58 cases studied and one probably case of congenital Chagas’ disease. Two infected infants were born to chagasic women with HIV infection and were diagnosed by parasitolological assays (microhematocrit, quantitative buffy coat-QBC or artificial xenodiagnosis). In both cases the placenta revealed T. cruzi and HIV p24 antigens detected by immunohistochemistry. In one case, a 14-week old abortus, the diagnosis of congenital T. cruzi infection was confirmed by immunohistochemistry. The other probable infection, a 30-week old stillborn, the parasites were found in the placenta and umbilical cord. The Western blot method using trypomastigote excreted/secreted antigens of T. cruzi (TESA) was positive for IgG antibodies in 54/55 newborns and for IgM in 1/55 newborns. One of the two newborns with circulating parasites had no detectable IgG or IgM antibodies. The assessment of IgG antibodies in the sera of pregnant women and their newborns was performed by ELISA using two different T. cruzi antigens: an alkaline extract of epimastigotes (EAE) and trypomastigote excreted/secreted antigens (TESA). The analysis showed a linear correlation between maternal and newborn IgG antibody titers at birth. A transmissão congênita da doença de Chagas continua a ser um problema no Brasil. Em um estudo com 58 recém-nascidos, de 57 mães com a forma crônica da doença de Chagas, selecionadas em três Instituições de Saúde da Cidade de São Paulo, a transmissão congênita foi demonstrada em 5,17% (3/58) dos casos, com um provável caso confirmado somente pelo achado de antígenos do T. cruzi na placenta e cordão umbilical. Os testes parasitológicos (microhematócrito, quantitative buffy coat-QBC ou xenodiagnóstico artificial) foram capazes de diagnosticar dois casos congênitos de infecção pelo T. cruzi, nascidos de mulheres chagásicas com infecção pelo HIV. A imunohistoquímica efetuada nestas duas placentas foi capaz de identificar formas amastigotas e antígenos do T. cruzi. A infecção congênita foi confirmada a nível placentário em outros dois casos, e a nível fetal em um destes casos por imunohistoquímica. O Immunoblotting utilizando antígenos excretados/secretados de formas tripomastigotas do T. cruzi (TESA-blot), detectou anticorpos IgG em 54/55 dos casos e IgM em 1/55. Nos dois casos congênitos um apresentou anticorpos IgG e IgM o no outro não foram detectados anticorpos IgG ou IgM anti T. cruzi, apesar do achado de parasitas circulantes.