What Is Cyclosporiasis? Symptoms, Treatment and Prevention as US Outbreak Grows
The US is investigating a growing cyclosporiasis outbreak after Michigan reported 572 cases, with the source still unknown. Health officials suspect contaminated fresh produce based on previous outbreaks. Here's what cyclosporiasis is, how it spreads, its symptoms, treatment, and the precautions experts recommend to reduce the risk of infection.
A growing outbreak of cyclosporiasis in the United States has prompted health officials to intensify investigations after Michigan reported a sharp rise in infections. According to the Michigan Department of Health and Human Services (MDHHS), the state has now recorded 572 cases, up from more than 300 reported just days earlier. While the source of the outbreak has not yet been identified, investigators suspect contaminated food based on patterns seen in previous Cyclospora outbreaks.
The latest surge comes days after infections were reported in several other parts of the country. Earlier, more than 145 cases were recorded across at least 17 US states, with New York, Texas and Illinois among those reporting the highest numbers. Around 20 people have been hospitalised, while no deaths have been linked to the outbreak. Listeria Outbreak in US Linked to Precooked Pasta Meals Leaves 6 People Dead and 25 Hospitalised, 18 States Affected.
What Is Cyclosporiasis?
Cyclosporiasis is an intestinal illness caused by Cyclospora cayetanensis, a microscopic parasite that infects the small intestine.
According to the US Centers for Disease Control and Prevention (CDC), the infection "usually causes watery diarrhea with frequent and sometimes explosive bowel movements." Hantavirus Outbreak: WHO Confirms 5 Cases Linked to Cruise Ship MV Hondius; 12 Countries Including UK, US and Canada Notified.
People become infected after consuming food or water contaminated with the parasite.
Unlike many food-borne illnesses, Cyclospora is not usually spread directly from one person to another. This is because the parasite requires several days or even weeks in the environment after being passed in human stool before it becomes capable of infecting another person.
Why Are Investigators Focusing on Fresh Produce?
Although officials have not confirmed the source of the current outbreak, fresh produce has repeatedly been linked to previous Cyclospora outbreaks in the United States and Canada.
According to Michigan health officials, foods associated with earlier outbreaks include:
- Bagged salad mixes and salad kits
- Fresh cilantro
- Fresh basil
- Raspberries
- Snow peas
- Green onions
Because these foods are often consumed raw, the parasite may survive if contaminated produce is not properly washed or cooked.
Health authorities are tracing food supply chains to determine where contamination may have occurred before the produce reached consumers.
What Are the Symptoms?
Symptoms generally appear about a week after consuming contaminated food or water, although the incubation period can range from two days to more than two weeks.
The hallmark symptom is watery diarrhoea which, according to the CDC, may involve "frequent and sometimes explosive bowel movements."
Other symptoms include:
- Stomach cramps
- Abdominal pain
- Nausea
- Vomiting
- Bloating
- Excessive gas
- Fatigue
- Weakness
- Loss of appetite
- Weight loss
- Mild fever in some cases
Although the infection is not usually life-threatening, it can persist for several weeks or recur after symptoms initially improve. Prolonged diarrhoea also increases the risk of dehydration, particularly among children, older adults and people with weakened immune systems.
How Is Cyclosporiasis Diagnosed and Treated?
Because its symptoms resemble several other gastrointestinal illnesses, doctors generally confirm cyclosporiasis through stool tests.
Health officials say the infection responds well to antibiotics.
Patients are also advised to rest and drink adequate fluids to replace water and electrolytes lost through diarrhoea. Most people recover completely after receiving appropriate treatment, although delayed diagnosis may prolong recovery.
How Can the Risk Be Reduced?
Until investigators identify the source of the outbreak, health officials recommend exercising extra caution while handling fresh produce.
The MDHHS advises consumers to:
- Buy whole heads of lettuce instead of pre-cut varieties.
- Remove the outer two to three layers of lettuce before washing.
- Wash remaining leaves thoroughly under running water.
- Separate cilantro and basil leaves while rinsing.
- Trim, peel and wash green onions thoroughly.
- Wash snow peas under running water while rubbing their surface.
- Consider frozen raspberries, as fresh raspberries are difficult to clean effectively.
Cooking also offers protection. According to Michigan health officials, heating food to 158 degrees Fahrenheit or higher kills the parasite.
Authorities further recommend washing hands before preparing meals, cleaning fruits and vegetables under safe running water, using clean drinking water and preventing cross-contamination between raw and ready-to-eat foods.
Background
Cyclosporiasis outbreaks have periodically occurred in North America and are often linked to contaminated fresh produce. Because Cyclospora cayetanensis requires time in the environment before becoming infectious, direct person-to-person transmission is uncommon. Public health investigations typically focus on tracing food supply chains to identify contaminated products and prevent additional infections.
(The above story first appeared on LatestLY on Jul 06, 2026 02:16 PM IST. For more news and updates on politics, world, sports, entertainment and lifestyle, log on to our website latestly.com).