Fig 1. Survival curve for marmosets intravenously exposed to decreasing doses of monkeypox virus.

Groups of animals (n = 3) were exposed to 10 fold reductions in viral titer in six different experiments. In order to proceed to the next lower dose, 100% of the animals had to succumb. Due to the severity of the disease, one dose (5x10⁶ PFU) was not evaluated.