Public Health England is investigating a national outbreak of Verocytotoxigenic E. coli (VTEC) serotype O157 phage type 8 vero-toxin type 2a infection that may be associated with consumption of pre-packed salad.
Genetic analysis of VTEC O157 isolates from people affected in the outbreak has identified 38 confirmed cases with one further probable case and four more awaiting test results. The confirmed cases all became ill between 29 July and 12 August and are widely distributed across England, with one case in Wales, but none in Scotland.
Questionnaires completed by people affected by the outbreak revealed that 33 of the 38 confirmed cases were exposed to pre-packed salad before becoming ill and 19 of those purchased salad through the same supermarket chain.
Further investigation suggested a link with two salad products sold by the retailer and containing a common ingredient. This ingredient can be traced back to three growers and a single packer/distributor. The investigation into the source of contamination is on-going.
More information about the investigation can be found here.