[Prevalence of human infections by Trypanosoma cruzi in blood banks in Venezuela].

Primary investigations carried out in blood banks in Venezuela during the 1950s, indicated that overall seroprevalence for Trypanosoma cruzi infection was 12% amongst blood donors. In Venezuela, blood donation is free. All public and private blood banks are controlled by the Ministry of Health. As from 1988 the ELISA technique was uniformly used in blood banks for the detection of T. cruzi infections. Annual median seroprevalence, between 1988 to 1992, was 1.20% (1.09-1.94%), with geographical variations between localities in several States. States with higher prevalence rates are located in the western and central part of Venezuela: Portuguesa, Lara, Trujillo, Cojedes and Carabobo. Due to difficulties in obtaining incidence rates for Chagas disease, it seems proper to use prevalence rates due to its greater stability; and in the specific case of Venezuela, due to a lesser severity and a higher survival of this disease at present. Considering that there is little to be offered to the seropositive individual, repeatability is avowed for serological diagnosis. Specificity should be strived for in the light of lower prevalence rates at present.