What is cyclospora? Diarrhoea symptoms, foods linked to US outbreak

Published 16 July 2026 · health

Cyclospora cases are rising across the US. Here’s what to know about symptoms, spread, treatment and prevention. United States health officials are investigating a growing

Cyclospora cases are rising across the US. Here’s what to know about symptoms, spread, treatment and prevention. United States health officials are investigating a growing cyclospora outbreak after infections surged across the country this year. Since May 1, the Centers for Disease Control and Prevention (CDC) has confirmed 1,645 domestically acquired cases and is reviewing more than 5,100 additional reports to determine whether they are also linked to the outbreak. The agency expects the number of infections to continue rising through August. While the illness is rarely life-threatening, it can cause prolonged gastrointestinal symptoms and is usually treated with antibiotics. Here is what we know about the virus and the outbreak What is cyclospora? Cyclospora is a tiny parasite that can only be seen under a microscope. It causes an intestinal illness called cyclosporiasis. Once inside the body, cyclospora infects the intestines and can cause symptoms that last for weeks if they are not treated. Unlike many other foodborne illnesses, cyclospora does not usually spread directly from one person to another. After leaving the body in a bowel movement, the parasite needs several days to weeks in the environment before it can infect someone else. Cyclospora infections are less common than illnesses caused by bacteria such as salmonella or E coli. However, outbreaks in the US have become more frequent over the past decade. Health experts say this is likely due to better testing and environmental conditions, such as warmer weather, that help the parasite survive. How do people get infected with cyclospora? According to the CDC, people become infected with cyclospora after eating food or drinking water contaminated with the parasite, usually when human waste enters the food or water supply. Fresh produce, including leafy greens, herbs and berries, has been linked to past outbreaks because these foods are often eaten raw and may be exposed to contaminated irrigation or washing water. Health officials have not yet identified the source of the current US outbreak.

The FDA is tracing several types of fresh produce through the supply chain to determine where the contamination occurred. The investigation includes lettuce identified by Michigan health officials as a possible source, although authorities say no specific produce item, grower or supplier has been confirmed as the cause. As part of its investigation, the FDA is interviewing infected people about what they ate before becoming sick and is then following those foods back through distributors and suppliers, sometimes all the way to the farm where they were grown. What foods are commonly linked to cyclospora? In previous outbreaks, cyclospora has most often been traced to fresh fruits and vegetables that are eaten raw. Foods linked to infections include lettuce, bagged salad mixes, cilantro, basil, raspberries, snap peas, coleslaw, vegetable trays and fresh fruit mixes. Taco Bell has reportedly removed lettuce, cilantro, pico de gallo and guacamole from the menu at some locations as a precaution while health officials investigate the outbreak. Experts also recommend taking extra care when handling fresh produce. Washing fruits and vegetables thoroughly at home, even if they are labelled “pre-washed”, may help reduce the risk of contamination. What are the symptoms of a cyclospora infection? According to the CDC, symptoms of a cyclospora infection usually appear about a week after a person eats contaminated food or drinks contaminated water, although they can develop as early as two days or as late as two weeks after exposure. The most common symptom is frequent, watery diarrhoea, but the infection can also cause loss of appetite, weight loss, stomach cramps, bloating, gas, nausea and extreme tiredness. Some people may also experience vomiting, body aches, headaches, a low-grade fever or other flu-like symptoms. Others, particularly those who live in areas where cyclospora is common, may have no symptoms at all. How can you prevent it? Good food hygiene can help lower the risk of infection, although washing produce does not always remove the parasite.