Prevention of transfusional Trypanosoma cruzi infection in Latin America

Abstract

Trypanosoma cruzi is a protozoan infection widely spread in Latin America, from Mexico in the north to Argentina and Chile in the south. The second most important way of acquiring the infection is by blood transfusion. Even if most countries of Latin America have law/decree/norms, that make mandatory the screening of blood donors for infectious diseases, including T. cruzi (El Salvador and Nicaragua do not have laws on the subject), there is usually no enforcement or it is very lax. Analysis of published serologic surveys of T. cruzi antibodies in blood donors done in 1993, indicating the number of donors and screening coverage for T. cruzi in ten countries of Central and South America indicated that the probability of receiving a potentially infected transfusion unit in each country varied from 1,096 per 10,000 transfusions in Bolivia, the highest, to 13.02 or 13.86 per 10,000 transfusions in Honduras and Venezuela respectively, where screening coverage was 100%. On the other hand the probability of transmitting a T. cruzi infected unit was 219/10,000 in Bolivia, 24/10,000 in Colombia, 17/10,000 in El Salvador, and around 2-12/10,000 for the seven other countries. Infectivity risks defined as the likelihood of being infected when receiving an infected transfusion unit were assumed to be 20% for T. cruzi. Based on this, estimates of the absolute number of infections induced by transfusion indicated that they were 832, 236, and 875 in Bolivia, Chile and Colombia respectively. In all the other countries varied from seven in Honduras to 85 in El Salvador. Since 1993, the situation has improved. At that time only Honduras and Venezuela screened 100% of donors, while seven countries, Argentina, Colombia, El Salvador, Honduras, Paraguay, Uruguay and Venezuela, did the same in 1996. In Central America, without information from Guatemala, the screening of donors for T. cruzi prevented the transfusion of 1,481 infected units and the potential infection of 300 individuals in 1996. In the same year, in seven countries of South America, the screening prevented the transfusion of 36,017 infected units and 7, 201 potential cases of transfusional infection

Re-infestation of houses by Triatoma dimidiata after intra-domicile insecticide application in the Yucatán peninsula, Mexico

“…Because of difficulties associated with therapeutic treatment, and the elusive development of an effective vaccine, control of the transmission of Chagas disease remains based on vector control by insecticides (Silveira & Vinhaes 1999) and on blood bank screening (Schmuñis 1999). Vector control programs in South America have focused on the interruption of natural transmission by attacking domiciliated vector populations using pyrethroide insecticides (Silveira & Vinhaes 1999), and they have been enormously successful.…”

Prevalence of Trypanosoma cruzi infection in blood donors in El Salvador between 2001 and 2011

“…Furthermore, the MINSAL data did not include specific demographic data whose analysis, coupled with knowledge regarding T. cruzi infection through transfusion, could have provided more sensitive results. Nevertheless, we believe that these data were useful, as previous studies of Latin American countries using similar data [2,36,37] suggested that the prevalence of T. cruzi antibodies in blood donors is a good predictor of prevalence on a national scale, and that the findings provide important insights into the current epidemiology of Chagas disease in El Salvador.…”

Control de la infección por Trypanosoma cruzi en donantes de sangre de Colombia, 2003.

“…Excepto los liofilizados de plasma y los hemoderivados, todos los componentes de la sangre son infectantes (5)(6)(7). Se estima que el riesgo de adquirir la enfermedad de Chagas al recibir una unidad infectada oscila entre 20% y 40%, cifras que pueden incrementarse, entre otras causas, por la elevada prevalencia en la población, por el largo tiempo de latencia de la infección, que para el caso de Chagas puede ser de varios años, la elevada prevalencia en donantes de sangre, la baja cobertura del tamizaje de las unidades de sangre donadas, el número de unidades de sangre transfundidas, la larga supervivencia del parásito en las unidades de sangre almacenadas en refrigeración, la falta de canalización y confirmación de donantes reactivos sospechosos de estar infectados, y la deficiencia en los controles de calidad durante el procesamiento de la sangre y sus componentes (8,9).…”