O inquérito nacional de soroprevalência de avaliação do controle da doença de Chagas no Brasil (2001-2008)
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2011
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A survey for seroprevalence of Chagas disease was held in a representative sample of Brazilian individuals up to 5 years of age in all the rural
areas of Brazil, with the single exception of Rio de Janeiro State. Blood on filter paper was collected from 104,954 children and screened in
a single laboratory with two serological tests: indirect immunofluorescence and enzyme linked immunoassay. All samples with positive or
indetermined results, as well as 10% of all the negative samples were submitted to a quality control reference laboratory, which performed
both tests a second time, as well as the western blot assay of TESA (Trypomastigote Excreted Secreted Antigen). All children with confirmed
final positive result (n = 104, prevalence = 0.1%) had a follow-up visit and were submitted to a second blood collection, this time a whole
blood sample. In addition, blood samples from the respective mothers and familiar members were collected. The infection was confirmed
in only 32 (0.03%) of those children. From them, 20 (0.025%) had maternal positive results, suggesting congenital transmission; 11 (0.01%)
had non-infected mothers, indicating a possible vectorial transmission; and in one whose mother had died the transmission mechanism
could not be elucidated. In further 41 visited children the infection was confirmed only in their mothers, suggesting passive transference of
maternal antibodies; in other 18, both child and mother were negative; and in 13 cases both were not localized. The 11 children that acquired
the infection presumably through the vector were distributed mainly in the Northeast region of Brazil (States of Piauí, Ceará, Rio Grande do
Norte, Paraíba and Alagoas), in addition to one case in Amazonas (North region) and another in Parana (South region). Remarkably, 60% of
the 20 cases of probably congenital transmission were from a single State, Rio Grande do Sul, with the remaining cases distributed in other
states. This is the first report demonstrating regional geographical differences in the vertical transmission of Chagas disease in Brazil, which
probably reflects the predominant Trypanosoma cruzi group IId and IIe (now TcV and TcVI) found in this state. Overall, these results show that
the regular and systematic control programs against the transmission of Chagas disease, together with socioeconomic changes observed in
Brazil in the last decades, interrupted the vectorial transmission in Brazil, resumed in the few cases found in this national survey. Furthermore
they reinforce the need for maintenance of control programs for the consolidation of this major advance in public health.
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Doença de Chagas, Inquérito, Soro-prevalência, Transmissão congênita, Crianças, Brasil, Chagas disease, Survey, Sero-prevalence, Congenital transmission, Children, Brazil
Citação
OSTERMAYER, Alejandro Luquetti; PASSOS, Afonso Dinis Costa; SILVEIRA, Antônio Carlos; FERREIRA, Antônio Walter; MACEDO, Vanize; PRATA, Aluízio Rosa. O inquérito nacional de soroprevalência de avaliação do controle da doença de Chagas no Brasil (2001-2008). Revista da Sociedade Brasileira de Medicina Tropical, Uberaba, v. 44, supl. 2, p. 108-121, 2011.