• South Australia had a small peak in the number of notifications at 412 in August 2006. Notifications decreased from then and stayed relatively low until the later part of 2008 when they began to increase. The state had peaks in November 2009 at 750 and then in October 2010 at 1056. The highest number of hospitalisations occurred between September and December 2010, peaking at 36 in November 2010.