IMMUNE-RESPONSE TO TRYPANOSOMA-CRUZI SHED ACUTE-PHASE ANTIGEN IN CHILDREN FROM AN ENDEMIC AREA FOR CHAGAS-DISEASE IN BOLIVIA

A field study of the immune response to the shed acute phase antigen ( SAPA) of Trypanosoma cruzi was carried out in the locality of Mizque, Cochabamba department, Bolivia. Schoolchildren (266), with an average of 8.6 +/- 3.6 years, were surveyed for parasitological and serologica l diagnosis, as well as antibodies directed against SAPA using the cor responding recombinant protein in ELISA. The antibodies against SAPA w ere shown in 82% of patients presenting positive serological diagnosis (IgG specific antibodies). The positive and negative predictive value s were 0.88. Antibodies anti-SAPA were shown in 80.8% of the chagasic patients in the initial stage of the infection (positive IgM serology, and/or positive buffy coat (BC) test) and in 81.4% of the patients in the indeterminate stags of the infection (positive IgG serology with negative BC and IgM tests). These results show that the anti-SAPA resp onse is not only present during the initial stage of the infection (fe w months) but extends some years after infection.