Here we show how the method performs at estimating R from single realization time series, produced by simulation with a known value of R 0 . In all instances the time series for human H5N1 cases in Vietnam (Figure 1a ) was used as introductions into the human population. For a choice of R 0 .1 in the simulation, any introduction readily develops into an epidemic. For R 0 ,1 each introduction leads to small outbreaks that eventually become extinguished.