From June 2006 to the end of August 2007, a total of 449 cases were reported, of which 302 in 2006 and 147 in 2007. The two outbreaks overlapped and not all cases were genotyped; therefore, it was not possible to determine the exact number of cases that occurred in each of the two outbreaks. Overall, 347/449 cases occurred amongst the Italian ethnic population and 102/449 amongst the Roma/Sinti population. Seventy-eight cases (17%) were laboratory confirmed while the remaining were epi-linked. The virus serotype was identified for fifty-seven cases (Serotype D4: n = 32; serotype B3: n = 25).