Figure 2. Effectiveness of nitroheterocyclic drugs in treating acute stage Trypanosoma cruzi infections when administered for 5 days at 50 mg kg⁻¹ bid.

(a) In vivo imaging of BALB/c mice infected with bioluminescent T. cruzi (CL Brener strain) and treated twice daily by the oral route with benznidazole (BZ), nifurtimox (NF), fexinidazole (FX), or fexinidazole sulfone (FXS). Treatment was initiated 14 days post-infection (n = 6). Representative ventral images of 2 mice are shown for each drug, at various time points. NT, non-treated (vehicle only). Where necessary, to confirm curative outcomes, mice were immunosuppressed by cyclophosphamide treatment on days 28, 32 and 36 post-infection (underlined with a red bar). (b) Assessment of drug activity by ex vivo imaging. Representative images of organs/images isolated 50 days post-infection from NT (i), NF-treated (ii and iii), FX-treated (iv), and FXS-treated (v) mice. In the case of NF treatment, examples of cured (ii) and non-cured (iii) mice are illustrated.