The Centers for Disease Control and Prevention said it has received 1,645 confirmed domestic cases of cyclosporiasis since May 1 in a lettuce parasite outbreak now spread across 34 states. Of the case-patients with available information, 141 have been hospitalized, and no deaths have been reported.
The number is drawing attention now because it is far above the 249 cases reported nationally by the same point last year. CDC is also aware of more than 5,100 additional reports that still need analysis before they can be counted as domestically acquired cyclosporiasis, a sign that the final total could climb further.
Cyclosporiasis is a gastrointestinal illness caused by the microscopic parasite Cyclospora. People become infected by consuming food or water contaminated with the parasite, and the illness is not usually spread directly from person to person. Previous outbreaks have been linked to contaminated fresh produce, which is why investigators are focusing on food exposures in the United States.
The illness often starts about a week after exposure, though symptoms can appear two to 14 days later. Watery diarrhea, loss of appetite, weight loss, bloating, nausea and fatigue are the most common complaints, with low-grade fever and vomiting less often reported. Without treatment, symptoms can come and go for days or even longer, and laboratory detection can be difficult even when patients are sick enough to seek care.
That is part of the problem facing public health officials: cyclosporiasis is often underdiagnosed and underreported, so the number already tallied by CDC is likely below the true toll. The agency says case counts typically rise in spring and summer, and it defines May 1 through August 31 as the annual cyclosporiasis season, but this year’s count has already moved well beyond what was seen at the same time last year.
CDC is working with FDA and state and local health departments to investigate multistate outbreaks of Cyclospora infections. The unresolved question is the one that matters most to people trying to avoid the next illness: which food is driving the outbreak, and whether the answer will come before the case count grows again.
