Seroprevalence to Trypanosoma cruzi in rural communities of the state of Querétaro (Mexico): Statistical evaluation of tests

ObjectivesThe detection of anti-Trypanosoma cruzi antibodies has become one of the priorities of the clinical establishments in the health sector, due both to the increase in positive cases found in transfusion centres as well as to the appearance of patients with characteristic Chagas cardiopathies that seek emergency treatment in the main hospitals of Querétaro (Mexico).Design and methodsThe present study seeks to establish for the first time the infection level of Trypanosoma cruzi, in the rural communities of this state and implement the preventive measures necessary to control and/or eradicate this infection. A transversal study was conducted, examining seriologically 1029 blood samples of the inhabitants of rural areas of the state of Querétaro, to detect anti-Trypanosoma cruzi antibodies.ResultsThe indirect serological diagnostic tests were indirect hemagglutination, enzymo-immunoenzymatic absorbent, recombinant ELISA, and indirect immunofluorescence. For the diagnostic evaluation of serological tests used, ELISA was considered the control test.ConclusionsThe first conclusion was that the two tests with the greatest serological reactivity were ELISA and recombinant ELISA, followed by IFA and IHA, respectively, with the final percentage of positives being 6.6%, far above the national mean of seroprevalence in Mexico (1.6%). On the other hand, the sensitivity, specificity, VP+, VP−, percentage of concordance and Kappa index of the recombinant ELISA tests, IFA, and IHA were determined against the control ELISA. It was found that ELISA and recombinant ELISA presented a greater sensitivity level, as well as the highest values for the different parameters studied.