Health authorities are alerting the public to a significant outbreak of cyclosporiasis across the United States, a foodborne parasitic infection that can cause prolonged and severe gastrointestinal illness and is frequently misdiagnosed as a routine stomach bug. The Centers for Disease Control and Prevention (CDC) has confirmed more than 1,600 domestic cases of cyclosporiasis since May, with an additional 5,100 cases currently under investigation.
The infection is caused by the microscopic parasite Cyclospora cayetanensis, which spreads through contaminated food or water. While symptoms can begin as early as two days after exposure, they often appear about a week later. Initial signs, such as abdominal pain, nausea, and watery diarrhea, can mimic those of a common viral stomach bug. However, cyclosporiasis typically lasts longer and presents with more severe symptoms, including profound watery, foul-smelling diarrhea and significant abdominal cramping, according to Dr. Kenneth Perry, an emergency physician.
Cyclosporiasis can also lead to a loss of appetite, fatigue, and weight loss. Unlike typical stomach bugs that usually resolve within 48 hours, this parasitic infection requires specific diagnostic attention. Standard stool tests and many gastrointestinal PCR panels do not detect Cyclospora. Healthcare providers must specifically request this test, and multiple stool samples collected on different days may be necessary for accurate diagnosis, as even symptomatic individuals might not shed enough of the parasite for detection in a single sample.
If symptoms strongly suggest cyclosporiasis despite an initial negative test, repeat screening may be warranted. For diagnosis, a primary care physician is often the best point of contact, as emergency departments typically do not screen for this parasite. Emergency departments are better suited for treating the downstream effects like dehydration, nausea, and diarrhea.
Patients experiencing diarrhea that persists for more than two to three days, worsens, or is accompanied by signs of dehydration should consult a physician. Unlike viral infections, cyclosporiasis is treatable with prescription antibiotics. The CDC recommends trimethoprim-sulfamethoxazole (TMP-SMX) as the primary treatment, with alternatives available for those who cannot take sulfa drugs. Staying hydrated is crucial, and doctors suggest using over-the-counter pediatric formulas for effective rehydration.
Individuals concerned about potential exposure can check FDA and CDC food safety alerts for information on recalled or implicated products. The outbreak has particularly affected Midwestern states, including Michigan and Ohio, though cases have been reported nationwide.