A widespread outbreak of cyclosporiasis, an intestinal illness caused by the parasite Cyclospora cayetanensis, has swept across 31 U.S. states, sickening thousands and prompting urgent public health investigations. The Centers for Disease Control and Prevention (CDC) and state health departments are racing to identify the contaminated food source, but so far, no common culprit has been found.

The Scale of the Outbreak

According to multiple reports, more than 1,700 confirmed cases have been reported as of late July 2025, with Michigan emerging as the epicenter—over 1,500 cases and 44 hospitalizations, as noted by MSN and USA Today. Other hard-hit states include Florida, Georgia, and New York, according to insidethemagic.net and MSN Georgia reports. The outbreak marks a significant surge compared to previous years, with cases detected in more than half of all states.

NPR News reported that the illness causes watery diarrhea (often described as 'explosive'), nausea, cramping, and fatigue, which can last weeks if untreated. The parasite is typically spread through contaminated fresh produce imported from tropical regions, but this year's outbreak has stumped investigators.

Conflicting Numbers and Reporting Challenges

Different sources have reported varying case counts, reflecting the dynamic nature of the outbreak. Mensjournal.com initially cited 1,100 cases, while MSN later updated to 1,700. The CDC's official count as of late July is around 1,100, but state-level data suggests underreporting. Inkl.com noted that the CDC downgraded parasite tracking a year ago, potentially hampering detection. Food Safety News reported nearly 150 cases in an earlier update, highlighting how rapidly the numbers have grown.

Michigan: The Epicenter

Michigan has been disproportionately affected. USA Today's detailed coverage explains that the state has seen over 1,500 cases and 44 hospitalizations, with health officials urging residents to practice strict hand hygiene and thoroughly wash produce. The Michigan Department of Health and Human Services is conducting interviews with patients to trace common food exposures. So far, no single restaurant chain or grocery item has been linked.

Florida and Georgia See Spikes

Florida has also experienced a notable rise in cases, with insidethemagic.net reporting that some families are postponing vacations to Disney World out of caution. The article highlights the economic ripple effect on tourism. Meanwhile, Georgia health officials have noted a spike in cases, as reported by MSN Georgia, and are advising clinicians to test for Cyclospora in patients with prolonged diarrhea.

What Is Cyclosporiasis?

Cyclosporiasis is caused by the microscopic parasite Cyclospora cayetanensis. Unlike bacteria, it requires days to weeks after ingestion to cause illness, making source tracing difficult. Symptoms include watery diarrhea, loss of appetite, weight loss, cramping, bloating, nausea, and fatigue. The illness can be treated with a specific antibiotic (trimethoprim-sulfamethoxazole), but without treatment, symptoms can persist for weeks.

The parasite is typically found in tropical and subtropical regions and is often linked to imported fresh produce such as raspberries, basil, cilantro, and lettuce. However, domestic produce has also been implicated in past outbreaks.

Public Health Response and Investigation

The CDC, FDA, and state health departments are collaborating on the investigation. The FDA is conducting traceback investigations on produce items reported by patients. However, as PBS.org notes, the lack of a single common food source has complicated efforts. Inkl.com reported that the CDC's decision to downgrade Cyclospora tracking a year ago may have reduced surveillance capacity, potentially delaying detection. Some experts argue that more resources are needed for foodborne illness surveillance.

Health officials advise the public to wash all fruits and vegetables thoroughly, cook produce when possible, and seek medical attention for persistent diarrhea. The CDC recommends that clinicians consider Cyclospora in patients with diarrheal illness lasting more than a few days, especially if they have traveled or consumed imported produce.

Historical Context and Past Outbreaks

Cyclospora outbreaks are not new. In 2018, a large outbreak linked to vegetable trays sickened hundreds. In 2020, another outbreak was traced to bagged salad mix. However, the current outbreak is notable for its rapid spread and high case count. The parasite's ability to survive on produce for extended periods makes it a persistent challenge for food safety.

Expert Views and Implications

Dr. Jennifer Johnson, an infectious disease specialist at the University of Michigan, told USA Today: 'This outbreak is alarming because we haven't identified the source. It could be a widely distributed product, which means more cases may emerge.' She emphasized the importance of handwashing and avoiding raw produce if at high risk.

Food safety advocate Sarah Klein of the Center for Science in the Public Interest commented to Food Safety News: 'This outbreak underscores the need for stronger import inspection and rapid traceback capabilities. Consumers shouldn't have to worry that their salad could cause weeks of diarrhea.'

The outbreak also raises questions about the impact of reduced public health funding. Inkl.com's report highlighted that the CDC's downgrade of Cyclospora tracking may have contributed to delayed detection. Critics argue that such cuts weaken the nation's ability to respond to foodborne outbreaks.

What You Can Do

Health officials recommend the following precautions:

• Wash all fresh fruits and vegetables thoroughly under running water before eating.
• Cook produce when possible, as heat kills the parasite.
• Practice good hand hygiene, especially after handling raw produce.
• If you develop watery diarrhea lasting more than a few days, see a healthcare provider and ask about Cyclospora testing.
• Avoid raw produce if you are immunocompromised or pregnant.

For most healthy individuals, the illness is self-limiting but can be severe. Those with symptoms should stay hydrated and seek medical care if dehydration occurs.

Looking Ahead

As the investigation continues, health officials expect more cases to be reported. The CDC is updating its case count regularly, and the FDA is working to trace the contamination to its source. In the meantime, consumers are advised to stay informed and take preventive measures.

This outbreak serves as a stark reminder of the vulnerabilities in the global food supply chain and the importance of robust public health surveillance. The coming weeks will be critical in determining whether the source can be identified and the outbreak contained.