FIG 1.
Optimal challenge dose determination in Nipah virus-infected Syrian hamsters. Hamsters were inoculated with Nipah virus (NiV) strain Malaysia via the intranasal (i.n.) route at 103 (orange, n = 9), 105 (blue, n = 8), or 107 (red, n = 9) TCID50 (A) or via the intraperitoneal (i.p.) route with 105 (green, n = 10) TCID50 (B). Graphs represent percent weight change from baseline (taken at −1 dpi), body temperatures, and daily clinical scores (scored from 0 to 10), with severity depicted by increasing intensity of red. Animals scoring ≥10 were humanely euthanized; any animals that succumbed to disease prior to euthanasia were allocated a score of 10. Gray boxes indicate the end of monitoring/scoring due to euthanasia/death. Individual animals are represented, with the black line indicating the mean value each day. (C) Combined survival curves for both i.n. and i.p. challenge routes indicating typical clinical signs observed at indicated times postinfection. Independently of inoculation dose and route, the initial disease presentation is respiratory distress beginning 3 to 6 dpi followed by a primarily neurological presentation at 8 to 20 dpi.