'Explosive diarrhoea' parasite outbreak in US: Over 1000 cases reported in weeks, Michigan worst hit

Published 11 July 2026 · health

Michigan health department issued advisory to thoroughly wash greens and remove the outer layer of lettuce in the wake of the virus outbreak. Cyclosporiasis cases

Michigan health department issued advisory to thoroughly wash greens and remove the outer layer of lettuce in the wake of the virus outbreak. Cyclosporiasis cases in the US What happens to the infected Michigan issues advisory for restaurants, kitchens More than half US states have reported an outbreak of Cyclosporiasis, an infection caused by a microscopic parasite that is leading to explosive diarrhoea. Michigan is the worst affected, as the state reported more than 1000 cases diagnosed in a two-week period. But 31 states reported the outbreak, where patients are getting infected by consuming food or water that contains this parasite.

No deaths have been reported so far from this infection.Between 1 May and 9 July there were 843 confirmed cases of cyclosporiasis in the US, according to data released on Thursday by the US Centers for Disease Control and Prevention (CDC).There are possibly hundreds more, with the public health agency saying on Friday it was aware of more than 1,500 cases that require further analysis to confirm the illness.No deaths have been reported, and 86 people were admitted to hospital, the CDC said.After Michigan, New York has seen the highest number of cases so far. Nearly 300 cases were reported there, state health officials said on 8 July.In Illinois, public health officials reported 141 cases on 7 July, calling it a "higher-than-average" figure, and 177 cases of cyclosporiasis have been reported in Ohio, according to officials there.Cyclosporiasis is an intestinal illness caused by a microscopic parasite, according to the CDC.

People can become infected by consuming food or water that contains the parasite. The illness is not usually life-threatening, according to the CDC, and is less common than other foodborne illnesses such as salmonella coli.People who are infected with cyclospora may or may not experience symptoms. The illness usually causes diarrhoea "with frequent and sometimes explosive bowel movements", says the public health agency.If untreated, the illness may last from a few days to over a month, and symptoms may return after appearing to dissipate.As Michigan has a higher number of cases, Michigan's health department has asked restaurants and kitchens to ensure that greens are thoroughly washed.

Cooking raspberries and leafy greens when possible, and removing outer layers of lettuce and green onions are the other instructions though it is not medically proved to be effective.