Congenital Chagas' disease in Salta, Argentina

Abstract

The immune response to Trypanosoma cruzi was studied in our hospital in 937 pregnant women (PW) and their 929 newborns (NB), group I; 4 NB from this center not included in the first group, group II and 35 NB derived from other centers, group III. Two positive results among indirect hemagglutination (IHA), complement fixation (CF) and indirect hemagglutination (IHA), complement fixation (CF) and indirect immunofluorescence (IIF) tests were considered as the criterion of previous infection with T. cruzi in PW. The presence of T. cruzi in blood, explored in fresh smears by serial micro-hematocrite and/or by xenodiagnosis, was the only criterion to define infection in NB. All NB were followed up by direct agglutination (DA) with or without 2 mercaptoethanol (DA-w2ME, DA-wo2ME) and IIF in order to establish the specific antibody kinetics. Clinical studies on NB with T. cruzi infection include routine laboratory tests. Benznidazole (3 to 7 mg/kg/day) and, in 1 case, nifurtimox (15 mg/kg/day) were employed as therapeutic agents. T. cruzi infection was confirmed in 149 PW (15.9%), table I. These chagasic mothers delivered 6 chagasic NB (CCHD-NB), (4%). Diagnosis of congenital Chagas' disease accounted for a total of 12 NB out of the 968 studied. 4 out of them were positive by both micro-hematocrite and blood smears and 7 by micro-hematocrite alone. Xenodiagnosis was performed in 2 NB resulting positive in both cases, table II. The most usual clinical findings included hepatomegaly (present in all cases), splenomegaly 8/12, jaundice 10/12 and prematurity 5/12, table 3. Laboratory findings showed anemia to be of hypochromic microcytic type in all cases. Other laboratory findings included lymphocytosis, normal erythrosedimentation, slight to moderate increase of transaminases in all cases, and elevated indirect bilirrubin in cases with jaundice, table 4. Analysis of cerebro spinal fluid in 6 CCh-NB revealed the presence of T. cruzi in 2 cases, plus abnormal cytochemical content in one of them, table 4. The serological reactions of infected and treated NB became negative between 4th and 8th month in all but 1 case that remained positive until 14th, fig. 1. A close correlation was found between DA and IIF. DA-w2ME) liter showed a significant drop during the initial phase of the controls. Benznidazole was successful in 11 out of the 12 CCh-NB. The remaining NB was effectively treated with nifurtimox. Therapeutic tolerance was satisfactory for both agents. These observations showed that congenital Chagas' disease in patients attending the hospital de Maternidad e Infancia from Salta appeared mostly oligosymptomatic. In agreeement with previous reports, micro-hematocrites appeared to be the method of choice for the rapid detection of T. cruzi infection in NB. Two concordant serologic reactions showed to be a satisfactory criterion for the follow up of infected NB. Due to scarce clinical manifestations of congenital Chagas' disease in NB, our results strongly suggest the surveillance of all offsprings to either confirm or discard the presence of infection.