[Neonatal Chagas disease: laboratory diagnosis during the first year of life].

Abstract This paper describes the parasitologic and serologic studies carried out during the first year of life in 721 pediatric patients born to mothers serologically positive for Chagas disease. The search for circulating trypomastigotes was performed by Strout, blood culture and/or Xenodiagnosis. In some cases, amastigotes were also detected in placenta and umbilical cord. Complement fixation test, indirect hemagglutination and indirect immunofluorescence were used to detect Trypanosoma cruzi antibodies. The dosage of total Ig by single radial immunodiffusion was also carried out. The results obtained showed an absolute correlation between parasite detection and the persistence of antibodies after six months of life. In the first group (GI) formed by 8 children, the diagnosis of congenital infection could not be confirmed because the isolation of T. cruzi was obtained only in later studies. In another 8 children grouped in GIII, it was impossible to detect parasitemia, and the diagnosis was reached by the serological positivity after six months of life. Finally, in 684 patients with anti-T. cruzi antibodies at birth, the serology became negative at the age of 3 months (GIV) or 6 months (GV). The methodology employed in this work is accessible to laboratories of medium complexity, and permits the diagnosis of congenital or neonatal chagasic infection with a high degree of reliability. On the other hand, it avoids unnecessary administration of trypanomicide drugs in a number of newborn and infants who have only received maternal antibodies at birth and were not infected by T. cruzi.