There have been 55 cases of E.coli O157 in Scotland in the first three months of 2011, compared to 14 last year and double the decade average of 25.
Health Protection Scotland (HPS) said more than half of the cases reported at the start of 2011 were found to be a new strain of the infection, phage type 8 (PT8), which has previously been reported in other parts of the U.K.