Cyclosporiasis in the United States 2026
Cyclosporiasis has emerged as one of the most closely watched foodborne illnesses in America this summer, with federal surveillance data confirming a fast-moving seasonal surge tied to fresh produce consumption. Caused by the microscopic parasite Cyclospora cayetanensis, this intestinal illness follows a predictable calendar pattern each year, with cases climbing sharply once warm-weather produce like basil, cilantro, and berries reaches peak consumption. In 2026, the Centers for Disease Control and Prevention (CDC) has confirmed 145 domestically acquired cases through mid-June alone, with additional state-level reporting since then pushing the combined national total well past 450 cases across 18 states.
This report lays out the most current, verified cyclosporiasis statistics for the United States in 2026, sourced exclusively from the CDC and its Morbidity and Mortality Weekly Report (MMWR) publications. Readers will find figures on this year’s outbreak scope, historical case trends dating back over a decade, the demographic breakdown of who is getting sick, hospitalization data, symptom timelines, and the specific antibiotic treatment regimen recommended by federal health authorities. Every number reflects the latest published federal data as of today, giving healthcare providers, food safety professionals, and the general public a single reliable reference point on this seasonal illness.
Understanding cyclosporiasis matters most during exactly this stretch of the calendar. The CDC formally defines the cyclosporiasis season as running from May 1 through August 31, the window when consumption of fresh herbs, leafy greens, and berries peaks nationwide, and when historically the overwhelming majority of annual cases have occurred. With the current season now roughly halfway through its typical span, and case counts already tracking well above what would be expected in a quiet year, this data carries direct, immediate relevance for anyone preparing or consuming fresh produce through the remainder of the summer.
Interesting Facts About Cyclosporiasis in the US 2026
Before the detailed breakdown, here is a quick-reference table of standout figures defining this year’s cyclosporiasis situation.
Key 2026 Cyclosporiasis Figures
Combined National Cases (through July) ████████████████████████████████████████ 450+
CDC-Confirmed Domestic Cases (Jun 16) ██████████████████████████████████░░░░░░ 145
States Reporting Cases ████████████████████████████████████████ 18
Hospitalizations (of 145 CDC cases) ██░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ 20
Michigan Cases Alone (early July) ██████████████████████████████████░░░░░░ 300+
| Metric | Figure |
|---|---|
| CDC-confirmed domestic cases, as of June 16, 2026 | 145 |
| Combined national case count, as of early July 2026 | 450+ |
| States reporting cases in 2026 | 18 |
| Hospitalizations among the 145 CDC-reported cases | 20 |
| Deaths reported in 2026 | 0 |
| Median age of domestic 2026 cases | 42 years |
| Share of 2026 domestic cases who were female | 61% |
| Michigan cases reported separately (early July 2026) | 300+ |
| Cyclosporiasis season, per CDC | May 1 – August 31 |
| States where cyclosporiasis is reportable | 47 states + D.C. + NYC |
Source: Centers for Disease Control and Prevention, “Surveillance of Cyclosporiasis,” updated June 18, 2026.
These figures show that 2026 is shaping up as a notably active cyclosporiasis season, even though the CDC has emphasized there is no confirmed evidence of a single, multistate outbreak linking all reported cases. The 145 cases confirmed through the agency’s official surveillance system as of June 16 represent only the federally verified portion of a much larger and still-growing national total, since fast-moving state-level clusters, particularly in Michigan, have added 300 or more additional cases that had not yet been incorporated into the CDC’s national count as of early July.
The demographic pattern is also worth noting: 61% of domestic cases were female, and the median patient age of 42 spans a wide range from 5 to 86 years old, showing that this illness affects people across every stage of life rather than concentrating in a single age group. With 20 of 145 federally confirmed cases requiring hospitalization and zero deaths reported, the illness remains serious but manageable when identified and treated promptly, a point the CDC has stressed repeatedly as investigators continue working to trace the source of this year’s elevated case counts.
The 2026 Cyclosporiasis Outbreak Timeline in the US
2026 Case Count Growth Over Time
May 1 - June 16 (CDC confirmed) ████████████████░░░░░░░░░░░░░░░░░░░░░░░░ 145
Early July (state + CDC combined) ████████████████████████████████████████ 450+
| Timeline Metric | Figure |
|---|---|
| Outbreak season start date, 2026 | May 1, 2026 |
| Median illness onset date (domestic cases) | May 13, 2026 |
| Range of illness onset dates | May 1 – June 6, 2026 |
| CDC surveillance data last updated | June 18, 2026 |
| Michigan’s typical annual case count (non-outbreak year) | ~50 cases |
| Michigan’s reported case count, early July 2026 | 300+ cases (six-fold increase) |
Source: Centers for Disease Control and Prevention, “Surveillance of Cyclosporiasis,” June 18, 2026; Michigan Department of Health and Human Services outbreak reporting, July 2026.
The timeline of this year’s cyclosporiasis activity shows a textbook seasonal pattern accelerating into something considerably larger than a typical year. Cases began appearing right at the start of the official May 1 season opening, with a median onset date of May 13, and by the CDC’s June 16 cutoff, 17 states had already reported cases through the federal system. Michigan’s outbreak, which emerged as a distinct and rapidly escalating cluster in late June, represents a striking outlier: the state typically records only around 50 cyclosporiasis cases in an entire year, yet reported more than 300 cases within just over a week, a roughly six-fold increase over its normal annual baseline.
This rapid escalation illustrates why cyclosporiasis surveillance operates as a rolling, continuously updated process rather than a single annual tally. Because state health departments often identify and report clusters faster than the federal system can incorporate and verify them, the true national case count during an active season is almost always higher than the most recently published CDC figure, a gap that has been especially pronounced during the Michigan cluster’s rapid growth through the first week of July.
Historical Cyclosporiasis Case Trends in the US
Annual US Cyclosporiasis Cases (Selected Years)
2019 ████████████████████████████████████████ 4,703
2018 █████████████████████████████░░░░░░░░░░░ 3,519
2017 ██████████░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ 1,194
2016 ████░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ 537
| Year | Reported US Cases |
|---|---|
| 2016 | 537 |
| 2017 | 1,194 |
| 2018 | 3,519 |
| 2019 | 4,703 |
| 2011–2015 (5-year combined total) | 2,207 |
| Lowest single year on record (2012) | 130 cases |
| Highest single year in 2011–2015 period (2013) | 798 cases |
Source: Centers for Disease Control and Prevention, “Cyclosporiasis Surveillance — United States, 2011–2015,” MMWR Surveillance Summaries; CDC Notes from the Field, Florida case data, 2021–2022.
Looking at the longer historical trend, national cyclosporiasis case counts have climbed dramatically over the past decade. Between 2016 and 2019, reported cases more than doubled year over year on two separate occasions, rising from 537 in 2016 to 1,194 in 2017, then nearly tripling to 3,519 in 2018, before reaching 4,703 cases in 2019, the highest annual total in the modern surveillance era. This roughly ninefold increase across just four years reflects both a genuine rise in infections tied to increased consumption of imported fresh produce and improvements in testing and reporting infrastructure across state health departments.
The earlier 2011–2015 surveillance period, by contrast, saw far smaller and more variable annual totals, ranging from just 130 cases in 2012 to 798 cases in 2013, with a combined five-year total of 2,207 cases nationally. This historical volatility underscores how heavily cyclosporiasis case counts depend on the specific produce items implicated in any given growing season, since a single contaminated shipment of cilantro, berries, or bagged salad greens can drive case counts many times higher than a typical baseline year, a pattern that appears to be repeating with Michigan’s 2026 cluster.
Cyclosporiasis Demographics and Hospitalization Data in the US 2026
2026 Domestic Case Demographics
Median Age ████████████████████████████████████████ 42 years
Female Share of Cases ████████████████████████████████░░░░░░░░ 61%
Hospitalization Rate ███████████░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ ~14%
| Demographic or Clinical Metric | Figure |
|---|---|
| Median patient age, domestic cases | 42 years |
| Age range, domestic cases | 5 to 86 years |
| Female share of domestic cases | 61% |
| Hospitalization rate among reported cases | 20 of 145 (~14%) |
| Deaths reported | 0 |
| Travel-associated cases (separate count) | 45 cases, ages 17–89, median age 43 |
| Female share of travel-associated cases | 62% |
Source: Centers for Disease Control and Prevention, “Surveillance of Cyclosporiasis,” June 18, 2026.
The demographic data confirms that cyclosporiasis affects a genuinely broad cross-section of the population rather than a narrow risk group. With patients ranging from 5 to 86 years old and a female share of 61% among domestically acquired cases, this pattern closely mirrors the separate cohort of 45 travel-associated cases reported by the CDC over the same period, where 62% of patients were also female and the median age was similarly in the low-to-mid 40s. This consistency between domestic and travel-related case profiles suggests that the underlying biological and behavioral risk factors for infection remain stable regardless of where exposure occurred.
The hospitalization figures offer useful context for how seriously to treat a suspected case. With 20 of 145 domestically acquired cases requiring hospitalization, roughly 14% of patients needed inpatient care, a meaningfully higher rate than the 3 of 45 hospitalizations seen among travel-associated cases, or about 7%. This gap may reflect differences in how quickly domestic cases were identified and treated versus the possibility that some travel-associated infections were recognized and managed earlier, though the CDC has not published a formal explanation for the difference. Critically, zero deaths have been reported in either group, reinforcing that cyclosporiasis, while unpleasant and occasionally severe, remains a rarely fatal illness when identified and managed appropriately.
Cyclosporiasis Symptoms in the US 2026
Reported Symptom Timeline
Incubation Period (average) ████████████████████████████████████████ 7 days
Incubation Period (maximum range) ████████████████████████████████████████████ 14+ days
Untreated Illness Duration ██████████████████████████████████████████████████ Up to 30+ days
| Symptom or Timeline Metric | Figure |
|---|---|
| Average incubation period | ~7 days (1 week) |
| Incubation period range | 2 days to 2+ weeks |
| Most common symptom | Watery diarrhea, sometimes explosive |
| Additional common symptoms | Cramping, nausea, fatigue, bloating, low-grade fever, vomiting, loss of appetite |
| Untreated illness duration | Days to a month or longer |
| Relapse possibility without treatment | Yes, one or more times |
Source: Centers for Disease Control and Prevention, “Clinical Overview of Cyclosporiasis,” and “About Cyclosporiasis,” 2026.
Cyclosporiasis symptoms typically begin about one week after a person ingests contaminated food or water, though the incubation period can range from as little as two days to more than two weeks in some cases. The hallmark symptom, and the one most frequently cited in this year’s outbreak reporting, is watery diarrhea with frequent, sometimes explosive, bowel movements, often accompanied by abdominal cramping, bloating, increased intestinal gas, nausea, fatigue, loss of appetite, and occasionally a low-grade fever or vomiting. Unlike faster-resolving illnesses such as norovirus, which typically clears within 24 to 72 hours, cyclosporiasis can persist for weeks if left untreated.
What makes cyclosporiasis particularly challenging for both patients and clinicians is its tendency to wax and wane. Left untreated, symptoms may appear to resolve entirely, only to return one or more times before the infection finally clears, a relapsing pattern that can stretch total illness duration to a month or longer in some cases. Because Cyclospora is a coccidian parasite that sheds oocysts intermittently in the stool, standard diarrhea test panels and routine stool cultures frequently miss the infection entirely, meaning healthcare providers must specifically request specialized testing, such as modified acid-fast staining or PCR analysis, when this illness is suspected.
Common Food Sources Linked to Cyclosporiasis Outbreaks in the US
Produce Items Historically Linked to US Cyclosporiasis Outbreaks
Cilantro (imported) ████████████████████████████████████████ Most frequently implicated
Bagged Salad/Lettuce Mixes ██████████████████████████████████░░░░░░ Frequently implicated
Basil ████████████████████████░░░░░░░░░░░░░░░░ Frequently implicated
Berries (raspberries) ████████████████████░░░░░░░░░░░░░░░░░░░ Occasionally implicated
| Prevention or Source Metric | Figure |
|---|---|
| Most frequently implicated produce item (historical outbreaks) | Cilantro imported from Mexico |
| 2023 Alabama restaurant outbreak case count | 47 cases (cilantro-linked) |
| 2021–2022 Florida bagged salad outbreak, share reporting salad exposure | 61% of respondents |
| Domestic-grown produce now also implicated | Yes, per recent CDC findings |
| Recall issued for 2026 outbreak source, as of this writing | None |
Source: Centers for Disease Control and Prevention, MMWR “Outbreak of Cyclosporiasis Among Patrons of a Mexican-Style Restaurant — Limestone County, Alabama, May–June 2023”; CDC Notes from the Field, Florida, 2021–2022.
Historical outbreak investigations consistently point to a narrow set of fresh produce items as the recurring culprits behind US cyclosporiasis clusters. A 2023 outbreak in Limestone County, Alabama, traced 47 cases directly to cilantro served at a Mexican-style restaurant, with investigators successfully completing a traceback to a specific source in Mexico. Similarly, a 2021–2022 Florida cluster that saw case counts double from 254 to 513 in a single year was substantially attributed to a prepackaged Caesar salad kit, with 61% of surveyed patients reporting exposure to bagged salad products before falling ill.
As of this writing, investigators working the 2026 season’s elevated case counts, including the rapidly growing Michigan cluster, have not yet identified or confirmed a common food source, and no recall has been issued in connection with this year’s cases. The CDC has noted that Cyclospora has increasingly been detected on domestically grown produce in recent years, a shift from the historical pattern of exclusively imported sources, which adds complexity to ongoing traceback investigations. Given this uncertainty, the agency’s standing guidance remains focused on general food safety practices: thoroughly washing all fresh produce under running water, trimming away bruised or damaged sections before consumption, practicing careful hand hygiene when handling raw fruits and vegetables, and exercising particular caution with high-risk items like cilantro, basil, raspberries, snow peas, and mesclun-style lettuce blends during peak growing season.
Cyclosporiasis Treatment and Testing in the US 2026
Recommended Treatment Regimen (Immunocompetent Adults)
TMP-SMX Standard Course ████████████████████████████████████████ 7-10 days
Cure Rate with Treatment ████████████████████████████████████████████████ 90%+
| Treatment or Testing Metric | Figure |
|---|---|
| First-line treatment | Trimethoprim-sulfamethoxazole (TMP-SMX) |
| Standard adult dosage | 160mg TMP / 800mg SMX, twice daily |
| Standard treatment duration | 7–10 days |
| Reported cure rate in immunocompetent patients | 90%+ |
| Alternative for sulfa-allergic patients | Ciprofloxacin (less effective) |
| Vaccine currently available | None |
Source: Centers for Disease Control and Prevention, “Clinical Care of Cyclosporiasis,” 2026.
The CDC identifies trimethoprim-sulfamethoxazole (TMP-SMX), sold under brand names including Bactrim, Septra, and Cotrim, as the clear treatment of choice for confirmed cyclosporiasis. The standard adult regimen calls for one double-strength tablet (160mg TMP plus 800mg SMX) taken orally twice a day for 7 to 10 days, a course that published clinical research shows achieves cure rates above 90% in patients with healthy immune systems. Pediatric patients aged 2 months to 18 years receive a weight-based dosage of 8–10mg/kg TMP and 40–50mg/kg SMX daily, split into two doses, over the same 7-to-10-day window.
For the subset of patients with sulfa allergies, who cannot safely take TMP-SMX, ciprofloxacin serves as the recommended alternative, though the CDC and published clinical literature are clear that this substitute is less effective than the first-line therapy. No vaccine currently exists for cyclosporiasis, making prompt diagnosis and treatment, alongside food and water safety precautions, the primary tools available for limiting the illness’s spread and severity. Notably, most people with healthy immune systems will eventually recover without any treatment at all, though the CDC cautions that untreated illness can persist far longer and carries a real risk of relapse, making early testing and treatment the more reliable path to a faster, more complete recovery.
Disclaimer: The data research report we present here is based on information found from various sources. We are not liable for any financial loss, errors, or damages of any kind that may result from the use of the information herein. We acknowledge that though we try to report accurately, we cannot verify the absolute facts of everything that has been represented.
