An 'Explosive' Diarrhea Bug Is Spreading Faster Than the Feds Can Track

The Trump administration made monitoring the cyclospora parasite voluntary. Now it's causing 'explosive' diarrhea across the U.S.

The federal government may be in the process of learning that it's hard to control what you choose not to observe. In this case it's cyclospora, a parasite that can infect humans and cause what the Centers for Disease Control and Prevention refers to as "explosive bowel movements."

The CDC says it knows of 843 cases of cyclosporiasis across 31 states. But a look at data collected by state shows that's a significant undercount.

Public health officials find themselves grappling with a seasonal emergency while armed with fragmented data and a hard-to-pin-down source for the outbreaks. It is often difficult to establish the source of food poisoning. Federal officials are looking at the supply chains for white and green onions, cucumbers and cilantro.

CDC says it's aware of 1,500 potential cases that authorities are working to confirm as domestically acquired cyclosporiasis. The agency says the age range is 5 to 88, with a median age of 44. There have been no reported deaths. The CDC also says it factors in a six-week lag between onset of symptoms and report to the agency.

Part of the feds' problem stems from the fact that in July 2025, the CDC scaled back its primary foodborne tracking system, the Foodborne Diseases Active Surveillance Network (aka FoodNet), citing budget constraints. Monitoring cyclospora became voluntary. That's made it harder for CDC to keep up with current outbreak data. Because cyclospora cannot be grown in a lab and requires quick and comprehensive cooperation across state lines to determine the point of origin, that decision has also made it harder to find the source of the food contamination.

There's an old adage that government is forever fighting the last war. Public health officials are at something of a decision point. They can live with delayed federal tallies and wash-your-vegetables warnings that may or may not change American behaviors. Or they can restore systems to catch foodborne parasites before they reach the dinner table. For now, the American salad bowl is a bit of a gamble.