Early Diagnosis of Congenital Trypanosoma cruzi Infection, Using Shed Acute Phase Antigen, in Ushuaia, Tierra del Fuego, Argentina

Abstract

Abstract. Chagas' disease, or American trypanosomiasis, is caused by the protozoan parasite Trypanasoma cruzi . It is estimated that 15,000 new cases of congenital T. cruzi transmission occur in the Americas each year. The aim of this study was to estimate the rate of congenital T. cruzi infection in infants born to infected women living in Ushuaia, Argentina, as well to assess a serologic test using Shed Acute Phase Antigen (SAPA) for a timely diagnosis of congenital infection. The rate of congenital infection among children in the study was 4.4% (3/68). Our results show that for infants younger than 30 days of age, matched blood samples from mother and infant were capable of identifying congenital transmission of infection using an enzyme-linked immunosorbent assay with SAPA. For infants older than 3 months, congenital infection could be ruled out using the same procedure.Chagas' disease, or American trypanosomiasis, is caused by the protozoan parasite Trypanasoma cruzi . It is a major cause of morbidity and mortality in Latin America.

Sensitivity and Specificity of an Operon Immunochromatographic Test in Serum and Whole-Blood Samples for the Diagnosis of Trypanosoma cruzi Infection in Spain, an Area of Nonendemicity

“…In fact, all the newborns showed positive concordant results by the two conventional tests, as was expected. Despite this, although antibody detection in the peripheral blood of newborns indirectly reflects the level of maternal antibodies, the antibodies may show a different pattern of recognition of certain epitopes which is not apparent when using total antigens (22).…”

First Colombian consensus on congenital Chagas and clinical approach for women of child-bearing age diagnosed with Chagas

“…According to different investigations, the time for the removal of maternal IgG antibodies varies. While a study in Santa Fe, Argentina, evidenced the elimination of maternal antibodies to at 6 months, 41 other investigators have proposed a threshold of 8 39.,42 or 9 months, 43,44 for the performance of these tests. Finally, there are some proposals to perform the serological tests at month 12 as it coincides with the date of application of vaccines and other public health interventions 45 .…”

Shed acute-phase antigen protein in an ELISA system for unequivocal diagnosis of congenital Chagas disease

“…An ELISA system [7] with the recombinant protein SAPA was developed in 1998 in Paraguay [2,5,103], and it is currently used in the public health system for the detection of IgG antibodies anti-SAPA in serum and in total blood with filter paper. The cut-off optical density of the ELISA-SAPA is 0.300 [2,5], with good discrimination between positive and negative infected infants aged 3-12 months.…”

“…An ELISA system [7] with the recombinant protein SAPA was developed in 1998 in Paraguay [2,5,103], and it is currently used in the public health system for the detection of IgG antibodies anti-SAPA in serum and in total blood with filter paper. The cut-off optical density of the ELISA-SAPA is 0.300 [2,5], with good discrimination between positive and negative infected infants aged 3-12 months. Our results, based on a large-scale study on serial screening of serum samples (n = 2283) from infants born to T. cruzi-infected mothers who were between 1 day and 1 year of age by an ELISA-SAPA assay [2,103], indicate that this is the best serological test allowing the earliest possible diagnosis of congenital T. cruzi infection (see Figure 1A & B).…”

“…Shed acute-phase antigen (SAPA) was described with main expression during the acute phase of T. cruzi infection associated with the infective stage of tripoamastigote [4]. The use of SAPA for the diagnosis of congenital Chagas' infection [2,5] and infection in children residing in endemic areas has been described previously [6].…”