Explosive diarrhoea hits thousands in 34 US states. Taco Bell lettuce to blame?
A rapidly growing outbreak of the foodborne Cyclospora parasite is sweeping across more than 30 US states, sending thousands on urgent, and often repeated, runs to the loo with explosive diarrhoea. With the source still unidentified, health officials are racing to trace the outbreak as cases continue to climb.
If you have ever had to make a desperate dash to the loo, imagine that happening several times a day, for weeks. That's what is happening to thousands of Americans right now, caught in one of the country's largest Cyclospora outbreaks in years, causing bouts of explosive diarrhoea. The United States has, across 34 states, recorded 1,645 laboratory-confirmed domestically acquired cases of cyclosporiasis, with 145 hospitalisations, while health officials are investigating more than 5,100 additional suspected infections.
The latest figures come from the US Centers for Disease Control and Prevention (CDC).
While the US is no stranger to cyclosporiasis outbreaks, having experienced similar surges in 2018 and 2019, the latest outbreak stands out for its scale. The Associated Press has described it as "one of the nation's largest in years". For comparison, the CDC had recorded just 249 cases nationwide by the same point last year.
THE EXPLOSIVE DIARRHOEA OUTBREAK ORIGINATED IN MICHIGAN
The outbreak is believed to have originated in Michigan, which continues to report the highest number of infections. Since then, the parasite has spread rapidly across the country. Federal health officials believe cases in at least four states — Michigan, Ohio, Kentucky and West Virginia — are linked, although they caution that multiple transmission patterns may be involved.
With more than 1,600 confirmed cases and over 5,100 additional suspected infections under review, the current outbreak could surpass the 2019 nationwide outbreak, which resulted in about 4,700 cases. Michigan has been particularly hard hit. A state that typically records fewer than 50 cases a year had reported more than 3,300 confirmed and suspected infections by Tuesday.
Health officials have yet to identify the precise source of the infections. A major food safety investigation is underway after authorities began examining whether Taco Bell restaurants could be linked to the outbreak. According to a report in The Washington Post, federal and state agencies are investigating whether the fast-food chain might have played a role in the spread of infections, particularly in Michigan.
No direct link between Taco Bell and the outbreak has been established. However, several Taco Bell outlets in the Detroit area temporarily stopped serving fresh ingredients, including lettuce, cilantro, onions and guacamole. Notices displayed at some restaurants reportedly informed customers that the items were unavailable because of a "national recall", reported The Post.
Investigators suspect that lettuce or other leafy greens may be the source of the outbreak. However, officials have stressed that no specific food item, grower, supplier or restaurant has been identified as responsible, and the investigation remains ongoing.
The response to the outbreak has also been complicated by changes to federal disease surveillance. In July 2025, the CDC scaled back its Foodborne Diseases Active Surveillance Network (FoodNet), ending active federal surveillance of Cyclospora and making routine monitoring more dependent on state health departments.
WHAT IS EXPLOSIVE DIARRHoEA CAUSING CYCLOSPORA PARASITE?
Cyclospora is a microscopic, single-celled parasite that infects the small intestine and causes cyclosporiasis, a foodborne illness best known for triggering frequent bouts of explosive diarrhoea, according to the US Centres for Disease Control and Prevention (CDC). While the illness is rarely life-threatening, it can last for weeks if left untreated and outbreaks are most common during the late spring and summer.
The parasite spreads through food or water contaminated with faeces. Unlike many other foodborne pathogens, Cyclospora is not usually transmitted directly from person to person because the parasite must first mature in the environment before it becomes infectious. In previous outbreaks, infections have been linked to contaminated fresh produce, including leafy greens, herbs and berries exposed to contaminated irrigation water.
Symptoms typically appear about one week after infection and include watery or explosive diarrhoea, loss of appetite, stomach cramps, bloating, nausea, fatigue, low-grade fever, weight loss and dehydration. Some infected people may have mild symptoms or none at all.
Treatment usually involves a course of prescription antibiotics. Most patients recover fully after completing the prescribed course, although symptoms can recur if left untreated.
To reduce the risk of infection, health authorities recommend washing fruits and vegetables thoroughly under running water, practising good hand hygiene, drinking safe water and avoiding food that may have been contaminated with human waste. However, because Cyclospora can cling to fresh produce, washing alone may not always remove the parasite completely, making proper food sourcing and handling equally important.
If you have ever had to make a desperate dash to the loo, imagine that happening several times a day, for weeks. That's what is happening to thousands of Americans right now, caught in one of the country's largest Cyclospora outbreaks in years, causing bouts of explosive diarrhoea. The United States has, across 34 states, recorded 1,645 laboratory-confirmed domestically acquired cases of cyclosporiasis, with 145 hospitalisations, while health officials are investigating more than 5,100 additional suspected infections.
The latest figures come from the US Centers for Disease Control and Prevention (CDC).
While the US is no stranger to cyclosporiasis outbreaks, having experienced similar surges in 2018 and 2019, the latest outbreak stands out for its scale. The Associated Press has described it as "one of the nation's largest in years". For comparison, the CDC had recorded just 249 cases nationwide by the same point last year.
THE EXPLOSIVE DIARRHOEA OUTBREAK ORIGINATED IN MICHIGAN
The outbreak is believed to have originated in Michigan, which continues to report the highest number of infections. Since then, the parasite has spread rapidly across the country. Federal health officials believe cases in at least four states — Michigan, Ohio, Kentucky and West Virginia — are linked, although they caution that multiple transmission patterns may be involved.
With more than 1,600 confirmed cases and over 5,100 additional suspected infections under review, the current outbreak could surpass the 2019 nationwide outbreak, which resulted in about 4,700 cases. Michigan has been particularly hard hit. A state that typically records fewer than 50 cases a year had reported more than 3,300 confirmed and suspected infections by Tuesday.
Health officials have yet to identify the precise source of the infections. A major food safety investigation is underway after authorities began examining whether Taco Bell restaurants could be linked to the outbreak. According to a report in The Washington Post, federal and state agencies are investigating whether the fast-food chain might have played a role in the spread of infections, particularly in Michigan.
No direct link between Taco Bell and the outbreak has been established. However, several Taco Bell outlets in the Detroit area temporarily stopped serving fresh ingredients, including lettuce, cilantro, onions and guacamole. Notices displayed at some restaurants reportedly informed customers that the items were unavailable because of a "national recall", reported The Post.
Investigators suspect that lettuce or other leafy greens may be the source of the outbreak. However, officials have stressed that no specific food item, grower, supplier or restaurant has been identified as responsible, and the investigation remains ongoing.
The response to the outbreak has also been complicated by changes to federal disease surveillance. In July 2025, the CDC scaled back its Foodborne Diseases Active Surveillance Network (FoodNet), ending active federal surveillance of Cyclospora and making routine monitoring more dependent on state health departments.
WHAT IS EXPLOSIVE DIARRHoEA CAUSING CYCLOSPORA PARASITE?
Cyclospora is a microscopic, single-celled parasite that infects the small intestine and causes cyclosporiasis, a foodborne illness best known for triggering frequent bouts of explosive diarrhoea, according to the US Centres for Disease Control and Prevention (CDC). While the illness is rarely life-threatening, it can last for weeks if left untreated and outbreaks are most common during the late spring and summer.
The parasite spreads through food or water contaminated with faeces. Unlike many other foodborne pathogens, Cyclospora is not usually transmitted directly from person to person because the parasite must first mature in the environment before it becomes infectious. In previous outbreaks, infections have been linked to contaminated fresh produce, including leafy greens, herbs and berries exposed to contaminated irrigation water.
Symptoms typically appear about one week after infection and include watery or explosive diarrhoea, loss of appetite, stomach cramps, bloating, nausea, fatigue, low-grade fever, weight loss and dehydration. Some infected people may have mild symptoms or none at all.
Treatment usually involves a course of prescription antibiotics. Most patients recover fully after completing the prescribed course, although symptoms can recur if left untreated.
To reduce the risk of infection, health authorities recommend washing fruits and vegetables thoroughly under running water, practising good hand hygiene, drinking safe water and avoiding food that may have been contaminated with human waste. However, because Cyclospora can cling to fresh produce, washing alone may not always remove the parasite completely, making proper food sourcing and handling equally important.
