Other observations also support the hypothesis of early community transmission in Victoria. We have previously established thresholds for the surveillance of influenza-like illness (ILI) in the state [33] . Normally ILI levels are below the baseline threshold when surveillance commences but, in 2009, ILI levels were above this threshold when surveillance commenced at the end of April [34] . None of the first 112 patients admitted with pH1N1 to seven hospitals in Melbourne had acquired their infection overseas [35] . Finally, it was possible to identify a presumed infectious source for only 3.7% of the first 1000 cases in Victoria (James Fielding, unpublished data).