EVALUATION OF A RECOMBINANT PROTEIN (RTC24) AND SYNTHETIC PEPTIDES IN ANTI-TRYPANOSOMA CRUZI POSITIVE SAMPLES FROM BLOOD BANK DONORS IN CHAGASIC ENDEMIC AREAS OF ECUADOR

Abstract

Chagas' disease, caused by the hemoflagellate Trypanosoma cruzi, affects around 17 million people in Central and South America (WHO, 1997) . The main route of transmission involves T cruzi infected triatomine insect bites, but other mechanisms of transmission such as blood transfusion or blood derived products have been reported to be responsible for fatal cases of acute Chagas' disease (Villalba et al., 1992) . Improved vector control by insecticide spraying and better management of blood banks in endemic areas are essential to reduce the disease transmission. Transfusion-associated transmission is not only a threat in the endemic countries but also in non-endemic areas due to migration of T. cruzi-infected individuals (Kirchoff, 1993) and the serological screening of blood banks could reduce the transfusion-associated transmission, avoiding the transportation of contaminated blood with the parasite. Actually, the use of serological screening in disease control is hindered by the cost of the assays and the sensitivity and secificity of the antigens used. Recently, with the development of the DNA technology, highly specific and sensitive recombinant antigens (Taibi et al., 1995) , as well as T. cruzi specific synthetic peptides, have been useful in the diagnosis of Chagas' disease (Burns Jr. et al., 1992) . In Ecuador, although Chagas' disease has been known to exist since 1927 (Arteaga, 1930) , the true prevalence of the disease is still unknown. In the country, blood bank screening for Chagas' disease is mandatory but testing in blood banks located in endemic areas is not regular. Recently, blood donors were found to be positive for antiT . cruzi antibodies in a vector-free region and even in non-endemic areas of the country (Grijalva et al., 1995, 1997) . Therefore, the screening of blood bank donors is a necessity in Ecuador. The present study was aimed to determine the prevalence of antiT . cruzi antibodies in Ecuadorian blood banks from two areas endemic for Chagas' disease. Serum samples from blood donors of the Red Cross Blood Bank of Guayaquil, province of Guayas (n= 1,423) , and from the Blood Bank of Machala, province of El Oro (n = 203) , were obtained during the period from March to June 1996 (Figure 1) . The samples were randomly collected and no distinction was made between volunteers, paid and frequently members. These samples collected were stored at -20°C until used. Total lysate obtained from T . cruzi epimastigotes