MICHIGAN – The “explosive diarrhea” that hit the U.S. this summer is fueled by a huge spike in cysticercosis cases, in what health officials are describing as one of the largest outbreaks in recent years.
As of mid-July 2026, the Centers for Disease Control and Prevention (CDC) has reported 1,645 confirmed locally transmitted cases since May 1, with more than 5,100 additional cases under investigation.
State reports show even higher numbers, with Michigan alone recording more than 1,500 cases, about 30 times the normal annual total, and nationwide cases in the thousands in more than 30 states.
Although no deaths have been reported, more than 140 people have been hospitalized, highlighting the potential severity of the disease.
(Source: cdc.gov)
This parasitic infection, often sensationalized in the headlines for causing 'explosive diarrhea', highlights the vulnerability of the fresh produce supply chain during the peak summer months.
Investigations by the CDC, FDA, and state health departments are ongoing and no single source has yet been confirmed, but past outbreaks have often been traced to imported fruits, herbs, and vegetables.
(Source: fda.gov)
What is cyclosporiasis?
Cyclosporiasis is an intestinal disease caused by the microscopic parasite Cyclospora caetanensis.
This single-celled organism infects the small intestine and disrupts normal digestive function.
Unlike bacteria and viruses, Cyclospora is a parasitic protozoan that requires time outside the human body in a warm, moist environment, typically one to two weeks, before it sporulates and becomes infectious.
This maturation period makes direct human-to-human transmission rare. Infections most often result from contaminated food or water.
(Source: cdc.gov)
This parasite is endemic in tropical and subtropical regions and thrives in soil and water contaminated with human feces.
The United States has experienced a seasonal spike in cases from May to August, coinciding with increased consumption of fresh produce and possible contamination during harvest or distribution in affected countries.
Improvements in diagnostic tests have also contributed to the increase in the number of reports in recent years.
(Source: fda.gov)
Symptoms: More than just stomach problems
The characteristic symptom is watery diarrhea, which occurs frequently (up to several times a day), sometimes explosively, and is accompanied by loud bowel sounds.
Other common signs include loss of appetite, significant weight loss, stomach cramps, bloating, increased gas, nausea, and extreme fatigue.
Less frequently, patients experience vomiting, low-grade fever, body aches, and headaches.
(Source: my.clevelandclinic.org)
The incubation period usually lasts about a week (from 2 days to more than 2 weeks).
Without treatment, symptoms can last from a few days to more than a month and may recur.
The disease impairs the absorption of nutrients and fluids in the small intestine, worsening dehydration and fatigue. It is especially dangerous for vulnerable groups such as the elderly, young children, and people with weakened immune systems.
Most recover on their own, but some may require medical intervention.
(Source: cdc.gov)
Cause and infection
Cyclospora* is spread only by the fecal-oral route through food or water contaminated with sporulating oocysts. In the United States, outbreaks are primarily associated with fresh foods that are consumed raw. According to previous research, raspberries, blueberries, blackberries, cilantro, parsley, basil, snow peas, mesclun lettuce, spinach, and salad mixes top the list. Washing produce under running water can reduce the risk, but it does not completely eliminate the risk as parasites can be stubborn. (Source: fda.gov) Contamination can occur on farms through irrigation with contaminated water, poor worker hygiene, or handling practices. Agricultural products imported from areas where cyclosporosis is endemic have become vectors for recurrence. In the current outbreak, clusters have suggested a possible link to widely distributed items, with some reports citing unconfirmed investigations involving restaurant chains such as Taco Bell. Traceback efforts are complicated when multiple clusters occur simultaneously. (Source: x.com)
Protection: Practical steps for consumers
Public health experts emphasize prevention through vigilance.
Thoroughly wash all fresh fruits and vegetables under running water and scrub any hard pieces with a clean brush. Avoid using soap or create a cleaning agent, as soap has not been proven to be more effective. If possible, peel or cook your produce. Practice safe food handling: Refrigerate perishable foods promptly to prevent cross-contamination and maintain good hand hygiene. Travelers to endemic areas should avoid consuming raw produce, unpeeled fruit, and untreated water. If symptoms occur, seek treatment immediately. Diagnosis requires a special stool test (routine egg and parasite tests may miss it and multiple samples may be required). The antibiotic trimethoprim-sulfamethoxazole (Bactrim) is the standard treatment for those who need it. Hydration is important. (Source: cdc.gov) There is no vaccine and reinfection is possible.
Spread and current range
Cases are surging in Michigan (more than 1,500), New York, Ohio, North Carolina, and Illinois, covering at least 31 to 34 states.
The onset of symptoms is concentrated from mid-June to late June. While some infections are travel-related, the majority of this wave has been locally acquired.
The real burden is likely to exceed the reported numbers because mild cases go undiagnosed.
govonestop.com
Statements from scientists and officials
Dr. Natasha Baghdasarian, Michigan's chief medical officer of health, said the state's case numbers are a “moving target” that is expected to rise further.
(Source: abcnews.com)
CDC officials note that enhanced surveillance and molecular tools are aiding the investigation, but pinpointing the exact source remains difficult because of the parasite's biology and complex supply chain.
FDA uses epidemiological, laboratory, and regulatory methods to conduct tracebacks.
(Source: usatoday.com)
Experts say that while cyclosporiasis is rarely fatal to healthy people, the high number of cases is straining medical resources and highlighting disparities in global food safety.
Ongoing research is focused on better detection methods, on-farm environmental controls, and rapid response protocols.
“This is a reminder that our food supply is interconnected,” one infectious disease expert noted in a recent report.
“Consumer awareness and industry practices both play an important role.”
(Source: medindia.net)
As the summer progresses, health officials urge the public to stay informed through updates from the CDC and to consult a health care provider about any persistent gastrointestinal symptoms.
Since the search is active and the season is not yet over, the best defense against this unwanted parasite remains careful meal preparation.
Disclaimer: This article was compiled using the AI ​​tool Grok on X and may contain inaccuracies.
