Mice were infected intranasally with 5×103 (n = 13, black triangles), 5×104 (n = 12, blue squares), or 5×105 (n = 12, red circles) PFU of maM35c4. Mice were monitored daily for weight loss (a) and survival (b). The severity of hemorrhage was scored on a scale of 0 (no hemorrhage) to 4 (complete hemorrhage) (c), and lung titers were measured (d), for 288–330+/+ mice infected with the 5×103 dose at day 3 p.i. (n = 4) and day 7 p.i. (n = 9), 5×104 dose at day 3 p.i. (n = 4) and day 7 p.i. (n = 8), and 5×105 dose at day 3 p.i. (n = 4) and day 7 p.i. (n = 4). All data are represented as means ± S.E.M. For lung titers below the limit of detection values were set at 1 to depict those mice on the graph.