Incubation period and generation time of Ebola virus disease (EVD). a) The probability density function of the incubation period, that is, the time from infection to illness onset, fitted to a lognormal distribution is shown. The mean and the standard deviation are 12.7 and 4.3 days, respectively . b) The generation time distribution, as collected from contact tracing data during the Ebola outbreak in Uganda, 2000, is fitted to a Weibull distribution. The mean and the standard deviation are 12.0 and 5.2 days, respectively.