CD8A and lymphopenia: We analyzed by flow cytometry the T cell subsets present in the blood and spleen at day 5 p.i. Significantly lower number of total CD4+ and CD8+ T cells were measured in the blood and spleen from infected mice compared to uninfected controls, indicating lymphopenia in both infected groups (Fig. 5A), and consistent with previous clinical studies (Potts and Rothman, 2008; Wilder-Smith et al, 2004).