4 things to know about cyclospora and climate change

The looming threat of cyclospora — a parasite often found in summer produce that causes severe gastrointestinal distress in humans — has struck fear into the hearts of salad enjoyers nationwide. On July 17, shortly after beginning its investigation into the multistate cyclosporiasis outbreak, the Food and Drug Administration announced a positive test result identifying cyclospora on shredded iceberg lettuce grown in Mexico for Taylor Farms, a major U.S. The company issued a voluntary recall — but the FDA walked back its statement two days later, describing the test as a “false positive” while insisting its investigation is “ongoing.” Representatives from Taylor Farms allegedly asked the FDA for more time before the agency recalled its products, according to a Wall Street Journal report.

At the time, the outbreak had been contained to five states in the Midwest, according to the Centers for Disease Control and Prevention. Since then, the CDC has linked four more states reporting cases of cyclosporiasis to contaminated lettuce from Taylor Farms, bringing the total of impacted states to nine. The CDC also stated that the outbreak has caused close to 2,000 cases of the illness — although that is likely an undercount.

(The CDC is also monitoring cases of cyclosporiasis that appear unrelated to this outbreak.) There are a number of reasons why it can be difficult to track cases of cyclosporiasis. For example, many people may experience and manage symptoms, which include persistent, watery diarrhea, at home without ever seeing a doctor. But the uneven rollout of information from public health authorities during this outbreak has further complicated matters.

Former federal food-safety officials have criticized the Trump administration’s handling of what is now considered the largest known cyclosporiasis outbreak in U.S. Unsaid in all of this is whether climate change and its impact on our globalized food system made this year’s outbreak more likely. “There are a couple things that make it a little difficult to fully assess what [the role of] climate change or changes in weather patterns could be,” said Jeffrey Griffiths, a professor of public health at the Tufts University School of Medicine.

“But I would say there’s still enough information that we have such that we can make some pretty reasonable inferences about…