Federal and state health officials are reportedly zeroing in on Taco Bell restaurants as a possible culprit in one of the biggest parasite outbreaks to slam the U.S. in years, a nasty bug that turns your guts into a nonstop disaster zone of explosive diarrhea and misery.

More than 4,000 people have already been sickened, the vast majority of them in Michigan, where victims are enduring days of gut-wrenching, bathroom-racing hell that has hospitalized at least 80 people so far.

The Washington Post reports that officials are probing whether contaminated fresh produce at the fast-food chain helped spread the Cyclospora parasite, which hitches a ride in feces-tainted veggies. No smoking gun has nailed Taco Bell or any single supplier yet, but the chain has yanked lettuce, cilantro, onions, pico de gallo, and guacamole from some Detroit-area locations after a nationwide recall notice surfaced last week.

Taco Bell insists it is playing it safe and putting customers first.

"The health and safety of our guests is our top priority," the company said in a statement obtained by the Post. "Public health officials have not confirmed a link to Taco Bell or any specific ingredient, so we have voluntarily pulled some items at select spots as a precaution while authorities continue their review."

Michigan is ground zero for the outbreak and is getting absolutely hammered, with a staggering 3,300-plus cases and hundreds more piling up daily as state health officials repeatedly flag leafy lettuce and salad greens as the leading suspect after interviewing more than 1,000 sick patients.

"Current results point to lettuce or salad greens as a potential source," Michigan's health department warned Monday. Meanwhile, federal officials at the CDC and FDA are being far more cautious, insisting there is no confirmed single multistate outbreak and that the numbers are not yet definitively unusual even as they log 145 cases across 17 states outside Michigan, along with 20 hospitalizations.

As we previously noted, Cyclospora cayetanensis is a microscopic parasite that loves hitching rides on fresh produce. Once it gets inside you it unleashes watery diarrhea, vicious cramps, vomiting, nausea, exhaustion, and fever that can drag on for days or even weeks if left untreated.

One victim, Cristy Cooper, recently spoke from her hospital bed to the New York Post about the nightmare that started June 25.

"This is worse than any flu I have ever gotten. It is just so miserable," she said. "I am worn out from it. I really am."