The Parasite You Can't Wash Off, Can't Catch From a Person, and Won't Feel for a Week

 There's a parasite spreading through the US right now that breaks almost every rule you've been taught about food safety. It's called Cyclospora cayetanensis, and Michigan is at the center of the largest outbreak the state has ever recorded — nearly 1,000 confirmed cases, against a normal annual average of around 50.

Why doesn't washing your produce work?

Because Cyclospora doesn't behave like the bacteria you're used to guarding against. It travels as an oocyst — a hardened shell engineered to survive in soil and water. The chlorine rinses that neutralize E. coli or salmonella on lettuce simply bounce off it. Food safety experts are blunt about this: rinsing does not remove the parasite. Heat is currently the only reliable kill method.

“Washing produce does not remove the microscopic parasite,” food safety investigators have confirmed as the outbreak has spread across Michigan and Ohio.

Can you catch it from someone in your own house?

No — and this is the part that trips people up. A freshly shed oocyst is biologically harmless. It has to sit in the environment, undisturbed, for one to two weeks to mature into an infectious form. That means Cyclospora cannot pass person-to-person, even between people sharing a bathroom. Every confirmed case traces back to contaminated water or raw produce, not contact with a sick person.

Why does it take a week to feel sick?

That same maturation window explains the delayed symptoms. By the time the “explosive,” watery diarrhea the CDC describes actually hits — often seven to fourteen days after exposure — the meal responsible is long forgotten. That lag is exactly why these outbreaks are so difficult for investigators to trace back to a single source.

Why does this only happen with produce, and why every summer?

Cyclospora is endemic to warm, tropical growing regions and typically hitches a ride into the US on fresh imported produce eaten raw — cilantro, basil, and berries have all been implicated in past outbreaks. That's also why cases spike predictably every summer, when imported fresh produce consumption peaks.

What did Taco Bell actually do — and why?

Locations across Michigan posted signs pulling lettuce, guacamole, pico de gallo, and cilantro-onion blend, citing a nationwide recall. Beef, beans, and cheese stayed on the menu. That's not caution for caution's sake — it's a precise read of the biology. Raw produce is the only plausible vector; everything cooked is neutralized by heat. As of this week, health officials still haven't pinpointed the exact source, and the FDA has not issued a formal recall — leaving Taco Bell's move as a voluntary, precautionary step while the investigation continues.

The bottom line

A parasite that's completely defenseless the moment it leaves your gut somehow becomes untouchable by the time it reaches your plate — because it spent one to two quiet weeks in the dirt turning into a weapon. Cooking your produce this summer isn't paranoia. It's the only defense that actually works.

This is a sensitive health topic. If you're currently experiencing symptoms — persistent watery diarrhea, cramping, fatigue — contact a healthcare provider for testing and treatment rather than waiting it out.