Cyclosporiasis On the Rise in the United States, Exceeding 450 Cases

Clusters of cyclosporiasis—a gastrointestinal illness caused by the parasite Cyclospora—are being reported in the United States, affecting over 450 individuals across 18 states. Although cyclosporiasis is a nationally notifiable disease, the unusually high number of cases has sounded the alarm.^1,2

On July 1, 2026, the CDC announced 145 cases across 17 states from May 1, 2026, through June 16, 2026. However, these statistics did not include Michigan, which reported more than 300 cases on Thursday, July 2, 2026.^{1 -3}

“Cyclosporiasis cases may not be limited to these states with known cases. The true number of people sick with cyclosporiasis was likely higher than the number reported,” said the CDC. “This is because some people recover without medical care and are not tested for Cyclospora.”³

As of July 7, 2026, the rise in cases shows no evidence of being a single, multistate Cyclospora outbreak linking all cases. The CDC maintains an emphasis on engaging in general hygiene and food safety practices.³

What Is Cyclosporiasis?

Cyclosporiasis is a gastrointestinal illness contracted through exposure to water or food contaminated with waste, leading to stomach cramps, loss of appetite, fever (uncommon), nausea, vomiting, and severe diarrhea—the hallmark symptom of the illness making headlines. It is particularly common in the spring and summer when individuals eat more fruits and vegetables, namely basil, cilantro, spinach, and berries—which have all been linked to prior outbreaks. Cyclosporiasis can also be contracted through swimming pools, natural bodies of water, or water parks.¹

Symptoms of cyclosporiasis are latent, appearing around a week following initial infection—making it difficult to pinpoint the contaminated food source.¹

How Is Cyclosporiasis Treated?

Cyclosporiasis is treated with a course of trimethoprim-sulfamethoxazole (TMP-SMX), the antibiotic combination sold under brand names such as Bactrim and Septra. For patients with a sulfa allergy, alternative regimens exist, though they tend to be less well studied; clinicians typically consult infectious disease guidance on a case-by-case basis.²

Diagnosis of cyclosporiasis is a challenge. The routine stool culture ordered for acute diarrhea will not pick up Cyclospora; confirming infection requires a specific modified acid-fast stain or PCR assay that has to be requested by name. That gap has prompted health officials in Michigan to specifically urge clinicians to consider cyclosporiasis in patients presenting with unexplained gastrointestinal illness and to order the correct test rather than defaulting to standard panels.⁴

Left untreated, cyclosporiasis is rarely life-threatening but can be miserable and prolonged. Symptoms can drag on for weeks to over a month without appropriate therapy, and relapse is possible even after apparent recovery. With treatment, most patients improve within days.⁴

How Can You Protect Yourself Against Cyclosporiasis?

Prevention comes down to food handling basics^2,5:

• Wash produce thoroughly. Rinse all fruits and vegetables under running water before eating, cutting, or cooking them, and trim away any bruised or damaged areas first.
• Practice hand hygiene. Wash hands with soap and water both before and after handling raw produce.
• Be cautious with high-risk items. Basil, cilantro, spinach, raspberries, snow peas, and mesclun-type lettuce blends have repeatedly been implicated in past outbreaks, particularly when imported during peak growing season.
• Watch drinking and recreational water sources. Avoid swallowing water from pools, lakes, or untreated sources, since Cyclospora can spread through water contaminated with fecal matter.
• Seek care promptly if symptomatic. Because standard stool tests miss Cyclospora, patients with persistent watery diarrhea should ask their provider specifically about cyclosporiasis testing, especially if they live in or traveled through an affected area.

Since cyclosporiasis is not spread person-to-person, there is no need to isolate from family members—but anyone preparing food for others while symptomatic should be especially diligent about handwashing.⁵

As of this writing, no recall has been issued in connection with the multistate cyclosporiasis clusters, and investigators in Michigan and at the federal level have not pinpointed a common food source.⁴ The CDC and FDA continue to update their respective outbreak pages as new information becomes available.

REFERENCES

1. Rabin R. Clusters of Severe Stomach Illness Reported Across the U.S. New York Times. Updated July 6, 2026. Accessed July 7, 2026. https://www.nytimes.com/2026/07/02/well/cyclospora-infection-united-states.html?unlocked_article_code=1.v1A.ThZp.ZTg6nedEe351&smid=url-share

2. Cyclosporiasis Outbreak 2026: 300 Cases in Michigan, 18 States Affected: What to Know. Virus Watcher. July 4, 2026. Accessed July 7, 2026. https://viruswatcher.com/blog/cyclosporiasis-outbreak-2026

3. Surveillance of Cyclosporiasis. CDC. Update July 1, 2026. Accessed July 7, 2026. https://www.cdc.gov/cyclosporiasis/php/surveillance/index.html

4. Vega E. Michigan Has More Than 300 Cyclospora Cases and No Food Source Has Been Found. Medical Daily. July 6, 2026. Accessed July 7, 2026. https://www.medicaldaily.com/michigan-cyclospora-outbreak-300-cases-stool-test-2026-475955

5. Kee C. Explosive diarrhea parasite’ sickens 170 in Michigan, hospitalizes at least 20 nationwide. NBC News. July 3, 2026. Accessed July 7, 2026. https://www.nbcnews.com/health/health-news/explosive-diarrhea-parasite-michigan-cyclosporiasis-illness-rcna352848