The CDC’s Morbidity and Mortality Weekly Report (MMWR) has released its report on the cyclospora outbreak that sickened more than 600 people in the U.S. this summer. During June through August 2013, there were 643 cases of the parasitic disease reported from 25 states. Texas had the most cases with 278, followed by Iowa at 153 and Nebraska at 86. By comparison, in 2012 there were 123 cases of cyclosporiasis in the United States for the whole year.
In Iowa and Nebraska, the outbreak was linked to salads imported from Mexico by Taylor Farms de Mexico served at Olive Garden and Red Lobster restaurants. But the Texas outbreak stumped public health officials for weeks. The CDC worked with state and local doctors and researchers in Texas to investigate the outbreak in that state. They identified a number of people who ate at “restaurant A” after June 1, 2013. Of 30 people who ate there, 22 had laboratory-confirmed cases of Cyclocspora cayetanensis infections. A case control study using 21 of those case-patients was conducted.
The patients were asked about the meals they ate at the unidentified restaurant using the menu. Four fresh produce ingredients were identified that had a statistically significant association with illness. They included fresh cilantro, whole onions, garlic, and tomatoes. Only fresh cilantro was eaten by all of the case-patients in the study. Salsas made by the restaurant were also suspect, since they were made with fresh cilantro.
Traceback information found that the cilantro came from Puebla, Mexico. Lettuce served at “restaurant A” was not sourced from the same producer implicated in the outbreak investigation in Iowa and Nebraska and it was not associated with illness.
The report concludes that “data from tracebacks and epidemiologic investigations in Texas, Iowa, and Nebraska indicate that more than one outbreak of cyclosporiasis occurred during summer 2013 in the United States.” Many of the cases were not solved and most likely will not be.
Image courtesy CDC
