Low seroprevalence of Trypanosoma cruzi infection and chronic chagasic cardiomyopathy in a region with abundance of triatomine vectors in Yucatan Peninsula of Mexico

The Yucatan Peninsula of Mexico is endemic with Chagas disease. The main vector responsible for Trypanosoma cruzi transmission is Triatoma dimidiata which is abundant in domestic, peridomestic and sylvan cycles. The abundance of vectors favours T. cruzi transmission and is a high risk for developing chronic chagasic cardiomyopathy (CCC). In the past 10 years, little information was available on parasite seroprevalence and the prevalence of CCC in the Yucatan Peninsula. In the present work, we studied two Mayan communities with a high abundance of T. dimidiata and a random serial sample of 233 patients with an altered electrocardiogram or cardiac failure admitted to the Regional Hospital. A homemade enzyme-linked immunosorbent assay and indirect immunofluorescence standardized techniques were used to detect anti-T. cruzi IgG. In addition, Mayan volunteers were monitored by electrocardiography. In the Mayan communities, 4.8% (3/63) subjects were positive for T. cruzi antibodies none of them presented electrocardiographic alterations, however in seronegative subjects were detected right or left ventricle hypertrophy in 25% (16/63). A remarkable finding was that 90% of the Mayan population recognized the vector and 65% of them had experienced contact with triatomines bites. At the Regional Hospital 0.42% (1/233) were positive for T. cruzi antibodies showing compatible diagnosis with CCC; the most frequent pathology in this population was hypertension in 65% (151/233) and the less frequent was dilated myocardiopathy 6% (14/233). In conclusion, the prevalence of T. cruzi infection and CCC can be considered low in Yucatan, Mexico.