Federal health officials have announced the conclusion of the largest recorded U.S. outbreak of cyclospora, a microscopic parasite responsible for an intestinal illness that led to more than 12,000 reported cases and over 1,000 hospitalizations.
The Centers for Disease Control and Prevention (CDC) stated on Friday that cases of the infection, known as cyclosporiasis, have significantly declined. The agency continues to investigate the exact source of the outbreak, which affected 21 states and Washington D.C. this year.
Officials have previously linked the outbreak to lettuce imported from Mexico by Taylor Farms, a major supplier for various food service companies. In response, Taylor Farms initiated a voluntary recall of lettuce originating from central Mexico. The fast-food chain Taco Bell confirmed it removed lettuce from the implicated supplier from its menu.
Cyclosporiasis, caused by the cyclospora parasite, is spread through contaminated food or water and can result in severe diarrhea, fatigue, nausea, and other gastrointestinal symptoms. The CDC notes that deaths from cyclosporiasis are uncommon, as the illness is not typically life-threatening. However, health officials in Michigan reported two deaths associated with the outbreak. These individuals had significant underlying health conditions that may have been exacerbated by cyclosporiasis and dehydration.
According to CDC data, nearly 20,000 confirmed cyclosporiasis cases have been recorded since May 1, a figure the agency acknowledges is likely an undercount of the true number of infections. While a substantial portion of these cases were traced to the contaminated lettuce, thousands of others were not directly linked to that specific product.
The 2019 outbreak, previously considered the worst in the U.S., saw approximately 4,700 cases nationwide. The current outbreak far surpassed that number, highlighting a significant increase in reported infections.
Health authorities in the United Kingdom also issued warnings regarding the outbreak, prompted by cases contracted by travelers returning from the U.S. The CDC's advisory notice confirmed the outbreak's conclusion due to a substantial decrease in reported cases.