A major outbreak of the parasite Cyclospora has sickened more than 22,000 people across 47 US states, causing two deaths in Michigan and 517 hospitalizations nationwide, federal health officials confirmed on Tuesday.
The Centers for Disease Control and Prevention confirmed 10,468 laboratory-confirmed cases of cyclosporiasis in an update on Tuesday, marking an increase of 6,707 cases from last week. Federal officials said the true scale of the outbreak could stretch past 22,000, as an additional 12,255 reports are still awaiting laboratory confirmation and investigation.
Michigan and Ohio are at the center of the outbreak, with local health departments in those two states reporting more than 15,000 cases and over 300 hospitalizations alone. Officials noted there is a reporting lag between local health authorities and federal data tracking systems.
The CDC, based in Atlanta, Georgia, acts as the national public health agency monitoring foodborne disease outbreaks across the country. State and local health departments track infections within their jurisdictions before submitting confirmed findings to federal authorities for nationwide aggregation.
Produce Contamination and Multi-State Spread
The updated figures come amid a major outbreak of the disease linked to shredded iceberg lettuce from Taylor Farms that was sold at Taco Bell and other retail stores.
In North Carolina, state health authorities are probing lettuce, cilantro and parsley as potential sources of infection. In Michigan, health officials have not pinpointed a specific source but have urged residents to thoroughly wash and trim certain produce items before consumption, including lettuce, leafy greens, cilantro, basil, green onions, raspberries and snow peas.
A total of 15 states have recorded cases in the major outbreak so far. Health officials are currently tracking six separate outbreaks of cyclosporiasis across the United States. Experts said the separate outbreaks do not mean that each cluster is unrelated, but rather suggest that health officials have identified a common food source for each cluster of infections.
Fresh produce can become contaminated when agricultural crops are washed or irrigated with water contaminated by human sewage. Agricultural supply chains that handle fresh leafy greens and herbs often distribute produce rapidly to restaurant chains such as Taco Bell and major grocery retailers, meaning contaminated lots can affect consumers across multiple states simultaneously.
Demographic Pattern and Previous Outbreaks
Nationwide, CDC officials said patients sickened with cyclosporiasis ranged in age from one to 98 years old, with an average age of 44 years, and 56 percent were female. Most patients became sick on July 4.
The current surge is significantly larger than the largest previously recorded US outbreak in 2019, which led to 4,703 domestic and internationally acquired cases that were primarily linked to fresh basil imported from Mexico alongside other causes.
Typically, the United States records only a few hundred cases every year, which are primarily linked to travelers returning from countries where the parasite is common, including Mexico, Central America, South America and the Caribbean. Previous domestic outbreaks have also been linked to bagged salad kits, cilantro, basil and other leafy greens.
Cyclospora cayetanensis is a microscopic single-celled parasite that infects the human digestive tract. Outbreaks tied to imported produce or regional agricultural processing plants often coincide with warm summer months when fresh produce consumption peaks across North America.
Symptoms, Transmission and Medical Treatment
Cyclospora is the parasite behind the intestinal illness cyclosporiasis, which is spread through consuming food or water contaminated with human feces. Symptoms include "explosive" diarrhea, abdominal cramps and vomiting in patients. The disease normally resolves in two weeks and is rarely fatal, although it can trigger potentially life-threatening dehydration.
Experts say it is also theoretically possible for people to become infected by touching surfaces that have been touched by a sick individual who did not wash their hands after using the toilet. Unlike norovirus or routine food poisoning, however, symptoms often come and go rather than resolving after a few days, and without treatment the illness can persist for weeks or repeatedly return.
Anyone with diarrhea lasting more than a few days should seek medical care and specifically ask for a cyclospora test, as it is not routinely ordered, Dr Swapnil Patel, vice chair of medicine at Hackensack Meridian Jersey Shore University Medical Center, told the Daily Mail.
The diagnostic test detects Cyclospora DNA in stool samples and typically requires one to three samples for confirmation. Treatment for the infection consists of the antibiotic trimethoprim-sulfamethoxazole, which is sold under the brand names Bactrim, Septra and Cotrim.
Hackensack Meridian Jersey Shore University Medical Center is a prominent regional hospital system in New Jersey. The antibiotic trimethoprim-sulfamethoxazole works by targeting bacterial and protozoan folate synthesis, serving as the standard prescription regimen for eliminating parasitic Cyclospora infections.
