RESUMEN
First and third generation leukocyte filters were used to filter blood units inoculated with trypomastigote forms of Trypanosoma cruzi. After blood filtration an aliquot of preor post-filtered blood was infected in isogenic mice. Infection evolution was followed by microscopic parasite count, indirect immunofluorescence and histopathological examination. All the animals that received pre-filtered blood (n = 27) accquired infection, while 26 percent of the mice injected with post-filtered blood (n = 27) were apparently not infected. A trend for late onset and peak of the parasitaemia was also observed among infected animals that received post-filtered blood (p<0.05). Additionally, the apparently non-infected mice also tested negative for both indirect immunofluorescence and histopathological examination. The results of this study, though very preliminary, suggest that that leukocyte filters might help to improve the safety of blood with regard to Trypanosoma, cruzi transmission.