US Cyclospora Outbreak: Over 1,600 Cases Confirmed, Officials Investigate Produce Sources
US health officials are investigating a growing cyclospora outbreak with 1,645 confirmed cases since May 1. The parasite causes prolonged diarrhea and is rarely life-threatening, but cases are four times higher than at the same point last year.
The US Centers for Disease Control and Prevention (CDC) is investigating a cyclosporiasis outbreak. Since May 1, 1,645 domestically acquired cases have been confirmed, with over 5,100 additional reports under review. The agency expects the number of infections to continue rising through August.
What is cyclospora?
Cyclospora is a microscopic parasite that causes cyclosporiasis, an intestinal illness. It infects the intestines and can cause symptoms lasting weeks without treatment. Unlike many foodborne illnesses, it does not spread directly from person to person; the parasite needs several days to weeks in the environment after leaving the body to become infectious. Cyclospora infections are less common than salmonella or E. coli, but outbreaks in the US have become more frequent over the past decade, likely due to better testing and warmer weather.
How do people get infected?
People become infected by consuming food or water contaminated with the parasite, usually through human waste entering the supply. Fresh produce—leafy greens, herbs, berries—has been linked to past outbreaks. The FDA is tracing several types of fresh produce, including lettuce identified by Michigan health officials as a possible source, but no specific item, grower, or supplier has been confirmed.
What foods are commonly linked?
In previous outbreaks, cyclospora has been traced to fresh fruits and vegetables eaten raw: lettuce, bagged salad mixes, cilantro, basil, raspberries, snap peas, coleslaw, vegetable trays, and fresh fruit mixes. As a precaution, Taco Bell has reportedly removed lettuce, cilantro, pico de gallo, and guacamole from some locations while the investigation continues.
What are the symptoms?
Symptoms usually appear about a week after exposure (range: 2 days to 2 weeks). The most common symptom is frequent, watery diarrhea. Other symptoms include loss of appetite, weight loss, stomach cramps, bloating, gas, nausea, and extreme fatigue. Some people may experience vomiting, body aches, headaches, low-grade fever, or flu-like symptoms. Others, especially those from areas where cyclospora is common, may have no symptoms.
How can you prevent it?
Good food hygiene helps reduce risk, though washing does not always remove the parasite. Recommendations: wash hands thoroughly before and after handling produce; rinse all produce under running water before eating, even if labeled “pre-washed”; use a clean brush for firm fruits and vegetables; refrigerate cut, peeled, or cooked produce within two hours.
Where has it spread in the US?
Infections have been reported in over 30 states. The hardest-hit state is Michigan (501–900 cases), followed by New York (161–300), North Carolina (81–160), and Illinois, Indiana, Kentucky, New Jersey, and Texas (31–80 each). Many other states have fewer than 30 cases.
Current situation
Cases are surging in southeastern Michigan, but this is not a national health emergency. CDC official Dianna Blau said there is no evidence the parasite has evolved to be more infectious. The case total so far is four times higher than at the same time last year. Michigan’s chief medical executive noted that the state’s aggressive investigation may partly explain the high numbers.
How long does infection last?
Without treatment, illness can last from several days to a month or longer. Diarrhea may improve and return, and fatigue can persist after other symptoms resolve.
How is it diagnosed?
Diagnosis requires testing a stool sample. Because the parasite may not be present in sufficient amounts, multiple samples may be needed. Laboratories use microscopy and PCR to detect the parasite.
What antibiotic is used?
The standard treatment is the antibiotic trimethoprim-sulfamethoxazole (TMP-SMX), sold as Bactrim or Septra. The course is usually 7–10 days, longer for immunocompromised individuals.
What should you do if you think you have it?
Since cyclosporiasis causes prolonged diarrhea, it is important to replace fluids by drinking water, broth, or electrolyte drinks. Avoid alcohol and caffeine. If antibiotics are prescribed, complete the full course even if symptoms improve.
