Four US states have confirmed Cyclospora cases associated with salad. More states are at risk of reporting cases. Wisconsin, Minnesota and Ohio have already reported cases. Illinois is being examined. The parasite causes long bouts of diarrhoea, stomach pain and weariness. Officials caution that fresh salads pose a risk. UK shoppers must rinse all bagged leaves well. Run cool water over each leaf before eating. Scrub firm greens like cabbage carefully. Soap is not needed; just water gets the job done.