Stomach cramping. Hard-to-control diarrhea. Fatigue. Dehydration. The symptoms of cyclosporiasis, the long-lasting gastrointestinal illness caused by a parasite found on produce, are easy to identify and hard to handle.
As of Friday, the Centers for Disease Control and Prevention said it had received reports of 843 cases of cyclosporiasis, caused by the parasite Cyclospora, in 31 states, including California. All cases confirmed by the CDC were acquired by eating food in the US; none of the patients had traveled internationally during the 14 days prior to when symptoms arose.
However, the true number of infections is likely higher because that number only reflects cases directly reported by states to the CDC, which can be a couple weeks behind state figures. (Michigan alone has reported 2,640 confirmed cases of cyclosporiasis as of Monday. The state’s health department is updating their count daily, whereas the federal CDC is every two weeks.) And, last summer, the CDC cut down the number of pathogens tracked by the Foodborne Diseases Active Surveillance Network (known as FoodNet) from eight to just two, which made tracking and reporting Cyclospora no longer mandatory.
Experts say there is also a lag between onset symptoms and reporting. Cyclosporiasis has a prolonged incubation period and diagnosis requires a specific stool test that doctors don’t typically order when patients come in with gastrointestinal issues.
Cyclosporiasis impacts a couple thousand people in the US every year, though this summer’s outbreak is notable due to the unusually high number of cases and the fact that a specific source hasn’t yet been identified. The US Food and Drug Administration is currently backtracing four different clusters of cyclosporiasis outbreaks to identify the offending sources and products, but there aren’t yet any answers. Symptoms can appear anywhere from two days to two weeks after infection.
California has reported 41 provisional cases of cyclosporiasis this year, which is within the expected range, a spokesperson for the California Department of Public Health told Gazetteer SF in an email. CDPH is not disclosing the locations where cases were reported, though they said only four of the cases reported since May were contracted domestically. “At this time, there are no known local outbreaks in California,” CDPH said. The agency is looking out for clusters of cases that could indicate transmission occurring in California.
Cyclosporiasis “usually causes watery diarrhea with frequent and sometimes explosive bowel movements” but symptoms also include nausea and fatigue. If not treated, the illness can last anywhere from a few days to several weeks, and can also wane and relapse. It can be treated with antibiotics.
Previous foodborne outbreaks of cyclosporiasis have been linked to various types of imported produce, including raspberries, basil, cilantro, snow peas, and mixed greens.
Google searches for “cyclospora” are up more than 5,000 percent this week compared to the same period last year. Restaurants around the US, including Taco Bell, are temporarily changing their menus while sources of the outbreak are still unclear.
Health officials advise that people thoroughly wash all their fresh produce, though the parasites are not easily rinsed away: The CDC says to thoroughly wash any fresh produce, scrub any firm produce with a brush, refrigerate quickly, and peel when you can. “Once fresh produce has been contaminated, removing or killing the microbial pathogens is very difficult,” the FDA says. Cooking fruits and vegetables at 185 degrees Fahrenheit or higher will kill Cyclospora.
