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The largest Cyclospora outbreak reported in the United States in recent years has taken a more serious turn, with Michigan confirming the first two deaths linked to the foodborne parasitic infection. State health authorities said both individuals had significant underlying medical conditions, with Cyclospora infection and severe dehydration believed to have contributed to their deaths.
The update comes as the outbreak continues to expand across the US, with Michigan alone reporting more than 11,200 suspected and confirmed cases and 193 hospitalisations. Nationally, the US Centers for Disease Control and Prevention (CDC) has confirmed over 6,700 laboratory-confirmed infections, while another 11,500 suspected cases remain under investigation. Health officials believe contaminated fresh produce-particularly lettuce or mixed salad greens, may be driving the outbreak, although investigations into the exact source remain ongoing.
The outbreak has drawn global attention because Cyclospora infections are usually sporadic and rarely fatal. However, in vulnerable groups, including older adults, people with weakened immune systems and those with chronic illnesses, persistent diarrhoea can lead to severe dehydration, electrolyte imbalance and other complications requiring hospitalisation.
The latest development follows weeks of rapidly rising case numbers in several US states, making the outbreak one of the country's largest documented foodborne parasitic events.
Michigan reports first Cyclospora-related deaths
The Michigan Department of Health and Human Services (MDHHS) confirmed that two residents have died after contracting cyclosporiasis, the illness caused by the parasite Cyclospora cayetanensis. Officials said both patients had serious pre-existing medical conditions that were likely worsened by the infection and dehydration. No additional details have been released to protect patient privacy.
As of July 30, Michigan had recorded 11,234 cases, including 193 hospitalisations and two deaths, making it the worst-affected state in the country.
Also Read: Cyclospora Illness Surges In The US: Could Lettuce Be The Cause Of Spread?
What is Cyclospora?
Cyclospora is a microscopic parasite that infects the small intestine and causes an illness known as cyclosporiasis. According to the CDC and the World Health Organization, people usually become infected after consuming food or water contaminated with the parasite.
Unlike many gastrointestinal infections, Cyclospora is unlikely to spread directly from one person to another because the parasite requires days to weeks in the environment before it becomes infectious.
Fresh produce, including leafy greens like lettuce, cilantro, basil, raspberries and other fruits and vegetables, has been implicated in previous outbreaks worldwide.
Symptoms to watch for
Symptoms typically appear around one week after exposure, although the incubation period can range from two days to more than two weeks.
Common symptoms include:
- Explosive or prolonged watery diarrhoea
- Loss of appetite
- Nausea and vomiting
- Abdominal cramps
- Bloating
- Fatigue
- Low-grade fever
- Weight loss
Without treatment, symptoms may persist for several weeks or recur over time. Severe dehydration is the biggest complication, especially among older adults, young children and immunocompromised individuals. CDC guidance notes that untreated illness can become prolonged and debilitating.
Is contaminated lettuce responsible?
Investigators from the CDC, the US Food and Drug Administration (FDA) and Michigan health authorities continue to examine the source of the outbreak.
Current evidence suggests lettuce or mixed salad greens may be involved, but officials stress that no single grower, supplier or specific produce item has been conclusively identified. Other food items remain under investigation.
Because fresh produce is often distributed widely before illnesses are recognised, identifying the exact source can take weeks or even months.
How is Cyclospora treated?
The CDC recommends the antibiotic combination trimethoprim-sulfamethoxazole (TMP-SMX) as the preferred treatment for cyclosporiasis. Patients who cannot take sulfa-based antibiotics may require supportive care, including oral or intravenous fluids to prevent dehydration.
Doctors also recommend seeking medical care if diarrhoea lasts more than a few days, is severe, or is accompanied by signs of dehydration such as dizziness, reduced urination or confusion.
Can the infection be prevented?
Health authorities recommend:
- Washing fruits and vegetables thoroughly before eating
- Drinking safe, treated water
- Practising good hand hygiene
- Avoiding food recalls and public health advisories
- Seeking medical attention for persistent diarrhoea after consuming fresh produce or travelling
- However, experts note that routine washing may not completely remove Cyclospora, making robust food safety practices across the supply chain essential.
The confirmation of two Cyclospora-related deaths marks a significant escalation in an outbreak that has already sickened thousands across the United States. Although fatalities remain rare, the outbreak highlights how foodborne parasitic infections can become life-threatening in vulnerable individuals, particularly when dehydration develops rapidly. With investigations still underway, public health agencies continue to urge vigilance, early diagnosis and prompt treatment while working to identify the contaminated food source responsible for the growing number of infections.
Disclaimer: This content including advice provides generic information only. It is in no way a substitute for a qualified medical opinion. Always consult a specialist or your own doctor for more information. NDTV does not claim responsibility for this information.