CDC links Cyclospora outbreak to lettuce and salad greens

Federal and state health officials said a multistate Cyclospora outbreak had grown to more than 400 reported illnesses in Michigan, Ohio, West Virginia and Kentucky, with sicknesses starting on or after June 22. Michigan’s health department said early investigation results pointed to lettuce or salad greens as a possible source, but no specific grower, supplier or product had been identified.

The scale in Michigan alone was far larger. By July 13, the Michigan Department of Health and Human Services said 2,640 cyclosporiasis cases had been reported since June 22, with the outbreak concentrated in Southeast Michigan. The state’s preliminary assessment came after more than 1,000 interviews with people who tested positive for Cyclospora, a parasite that causes an intestinal infection marked by diarrhea and other gastrointestinal symptoms.

Officials were still trying to pin down the source because the pattern does not look like a normal, item-by-item food recall. On July 5, Michigan health officials said they had not identified a specific produce grower, supplier or even a single produce type. Instead, investigators were working from interview data and illness patterns, while the Centers for Disease Control and Prevention said only 45 sick people reported traveling outside the United States before they became ill, a detail that made a foodborne source more likely than a travel-related one.

The CDC said the true number of sick people was likely higher than the reported totals because some people recover without medical care and never get tested. Since May 1, the agency had received reports of 1,645 confirmed domestic cyclosporiasis cases and knew of more than 5,100 additional cases that still required review to confirm where infection was acquired.

Health officials said people should watch for prolonged watery diarrhea, stomach cramps, nausea, fatigue and signs of dehydration, and seek medical care if symptoms are severe or do not improve. Michigan officials also advised consumers to choose whole heads of lettuce rather than prewashed bagged lettuce or salad mixes, remove the outer leaves, wash produce under running water and cook vegetables when possible.

Cyclospora outbreaks in the United States have repeatedly been tied to fresh produce, including raspberries, basil, cilantro, fruit mixes, snow peas, snap peas, lettuce and salad mixes. That history is one reason investigators are focusing on leafy greens now, even as they continue to say the outbreak source remains unconfirmed.