Four US states have confirmed Cyclospora cases associated with salad. More states could follow. Wisconsin, Minnesota and Ohio have already reported cases. Illinois is under investigation. The parasite leads to extended diarrhoea, abdominal cramps and fatigue. Officials caution that fresh salads pose a risk. UK shoppers are advised to rinse all bagged leaves well. Run cold water across each leaf before you eat. Scrub sturdy greens such as cabbage with care. Soap is unrequired; just water is sufficient.