Fig. 2From: Construction of the influenza A virus transmission tree in a college-based population: co-transmission and interactions between influenza A virusesConstructed transmission tree of influenza A virus: a The relative frequency of the generation intervals; b The average case reproduction number R t as it varies with time. Bars represent 95 % nonparametric bootstrap percentile confidence intervals generated from one million possible transmission trees sampled from the contact probabilities listed in Table 1Back to article page