Prevention of transfusional Trypanosoma cruzi infection in Latin America

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 mo st important way of acquiring the infection is by blood transfusion. Even i f most countries of Latin America have law/decree/norms, that make man; dat ory the screening of blood donors for infections diseases, including T. cru zi (El Salvador and Nicaragua do not have laws on the subject), there is us ually no enforcement or it is very lax. Analysis of published serologic surveys of T. cruzi antibodies in blood don ors done in 1993, indicating the number of donors and screening coverage fo r T. cruzi in ten countries of Central and South America indicated that the probability of receiving a potentially infected transfusion unit in each c ountry varied from 1,096 per 10,000 transfusions in Bolivia, the highest, t o 13.02 or 13.86 per 10,000 transfusions in Honduras and Venezuela respecti vely where screening coverage was 100%. On the other hand the probability o f transmitting a T. cruzi infected unit was 219/10,000 in Bolivia, 24/10,00 0 in Colombia, 1 7/10,000 In El Salvador; and around 2-12/10,000 for the se ven other countries. Infectivity risks defined as the likelihood of being infected when receivin g an infected transfusion unit were assumed to be 20% for T. cruzi. Based o n this, estimates of the absolute number of infections induced by transfusi on 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 Vene zuela screened 100% of donors, while seven countries, Argentina, Colombia, El Salvador; Honduras, Paraguay, Uruguay and Venezuela, did the same in 199 6. In Central America, without information from Guatemala, the screening of donors for T cruzi prevented the transfusion of 1,481 infected units and t he potential infection of 300 individuals in 1996. In the same year; in sev en countries of South America, the screening prevented the transfusion of 3 6 017 infected units and 7, 201 potential cases of transfusional infection.