1C). Rarely, parasite-positive areas were seen during the chronic phase PI3K inhibitor (data not shown). Histopathological analyses revealed that in T. cruzi-infected C3H/He mice, brain inflammation was restricted to the acute phase of infection, when inflammatory cells were seen in the parenchyma and perivascular cuffs with one or more layers of infiltrating cells ( Fig. 1D). In the acutely infected C3H/He mice, several CNS areas were affected including hippocampus ( Fig. 1D), a brain region involved in depression in mouse models ( Bahi and Dreyer, in press). In contrast, no inflammatory infiltrates were detected in the brain of acutely and chronically T. cruzi-infected C57BL/6

mice ( Fig. 1D), resembling the CNS of NI controls. These data are summarized in Table S1. Therefore, these models allowed us to test whether behavioral alterations were induced during chronic T. cruzi infection and whether they were a long-term consequence of acute CNS inflammation. To test whether behavioral alterations are present in T. cruzi infection, we initially subjected infected

mice to the open-field test and analyzed the numbers buy GSK2118436 of peripheral and central crossed lines and rearing episodes. Acutely infected C57BL/6 mice exhibited a significant (p < 0.001; t (11) > 5.124) decrease in locomotor/exploratory activity compared with the NI controls in five-, ten- and thirty-minute sessions ( Fig. S1A). Chronically T. cruzi-infected C57BL/6 mice also presented a significant decrease in locomotor/exploratory activity expressed as the reductions in the number of crossed peripheral (p < 0.0001; t (9) = 11.89) and central (p < 0.01; t Farnesyltransferase (9) = 4.107) lines and rearing episodes (p < 0.0001; t (9) = 8.888) in five-minute sessions ( Fig. S1B). This finding confirms our previous data ( Silva et al., 2010). Conversely, when T. cruzi-infected C3H/He mice were compared with sex- and age-matched NI controls, there were no significant differences (p > 0.05; t (6) < 1.500)

in the numbers of crossed peripheral and central lines or rearing episodes during the acute (30 dpi; Fig. 2A) or chronic (90 dpi; Fig. 2B) phases of infection in five-minute sessions of the open-field test. Furthermore, no significant (p > 0.05; t (11) < 1.000) behavioral alterations were detected in acutely ( Fig. S2A) or chronically ( Fig. S2B) T. cruzi-infected C3H/He mice when their performances in ten- and thirty-minute sessions of the open-field test were analyzed. Considering that sickness features may contribute to behavioral alterations such as decreases in spontaneous locomotor/exploratory activity ( Rogers et al., 2001), we further assessed sickness behavior by checking body weight loss (which reveals loss of appetite), apathy and increase in temperature (indicative of fever). During the recorded interval (from 7 to 150 dpi), apathy, characterized as prostration, was not detected in C3H/He and C57BL/6 mice infected with a low-level inoculum of the Colombian T. cruzi strain.