Analysis of amastigote replication on CK18 RNAi treated HeLa cells infected with different T. cruzi strains. HeLa cells were left untreated (A and D), or were transfected with control RNAi (B and E), or CK18 RNAi (C and F). These cells were then infected with tissue culture trypomastigotes of the Y (A-C) or CL-Brener (D-F) strains of T. cruzi. After 48 h, cells were fixed and stained with Giemsa. Magnification bar = 20 μM.