A parasite causing diarrhea has triggered a significant outbreak in the U.S., affecting over 1,000 individuals and leading to hospitalizations for dozens. Multiple states have reported cyclospora infections, characterized by symptoms like watery diarrhea, bloating, fever, and nausea. Although these cases are typical during spring and summer, the current outbreak is unusually large, marking one of the country’s most extensive occurrences, with no fatalities reported.
The Public Health Agency of Canada stated that there are no ongoing investigations into similar outbreaks in Canada, emphasizing that the parasite is not commonly found in Canadian food or drinking water sources.
Cyclospora is a small spherical parasite that often results in watery diarrhea with frequent and sometimes severe bowel movements, as per the U.S. Centers for Disease Control and Prevention. While the illness, known as cyclosporiasis, is usually non-life-threatening and can be treated with antibiotics, it spreads through feces and typically infects the intestines. The parasite is commonly transmitted through fresh fruits and vegetables, especially those like raspberries, blueberries, and lettuce that have crevices where the parasite can hide.
The outbreak’s cause remains uncertain, but food safety expert Lawrence Goodridge suggests a possible link to produce imported from regions like South and Central America, the Caribbean, Southeast Asia, or Africa. Symptoms may appear up to two weeks post-exposure and can persist for up to two months. Although cyclospora is less prevalent compared to other foodborne illnesses like salmonella and E. coli, recent years have seen an increase in reported cases, attributed to factors such as climate change and enhanced detection methods.
Michigan has reported a significant rise in cases, with 1,251 cases recorded, notably higher than the usual annual count of around 50 cases. Nearby Lucas County, Ohio, has reported 306 cases, while more than 400 cases have been registered in northwest Ohio. Additionally, 28 other states, including Illinois and New York, are investigating reported cases, with the outbreak’s source proving challenging to trace due to the short shelf life of fresh fruits and vegetables.
Despite the surge, the outbreak is not classified as a national health emergency, with experts indicating no evidence of the parasite evolving to become more infectious. While Michigan appears to have the highest concentration of cases, aggressive reporting may contribute to this perception. Previous notable outbreaks linked to cyclospora include instances involving Guatemalan raspberries in 1997 and Mexican basil in 2019.
Regarding Canada, the current outbreak has not impacted the country, with an average of 238 cyclosporiasis cases reported annually between 2004 and 2019. Canadians are advised to seek medical care and testing if they suspect illness and to take precautions when traveling to the U.S., such as avoiding certain fruits and vegetables or consuming only cooked or peelable produce. Washing produce may not eliminate the parasite, and additional measures like buying whole lettuce heads and freezing fruit can help reduce the risk, though not guarantee complete elimination.