Distribution of duration of clusters of S. Enteritidis and S. Typhimurium using the 0-, 5- and 10-SNP level thresholds in England, April 2014–March 2015. aIndividual national clusters, not shown, had durations of 57, 58, 66 and 134 days, respectively. bIndividual national clusters, not shown, had durations of 57, 58, 66 and 134 days, respectively.