California is one of the few states that health officials say the national cyclospora outbreak spared. Yet the state's own tally of the diarrhea-causing parasite has jumped from 41 cases in the first half of the year to 215 by mid-July — and the California Department of Public Health concedes it is "still investigating cases and the cause of the increase."

The distinction matters because it separates two stories that are easy to conflate. Nationally, cyclosporiasis has sickened tens of thousands and killed two people in Michigan, with investigators pointing to iceberg lettuce grown by Taylor Farms de Mexico. California, CDPH says, is not part of that outbreak — none of the implicated lettuce reached the state. But California's caseload has still climbed sharply above its own historical norm, and the leading explanation officials offer is not a tainted salad on local shelves. It's travel — and, possibly, the fact that a scary national headline has driven more people to get tested.

California health officials spent July reassuring residents that the state was an island of calm in a national cyclospora scare. The Centers for Disease Control and Prevention had logged 1,645 confirmed U.S. cases and was tracking more than 5,000 others; Michigan alone reported well over 4,000, and by early August the Associated Press confirmed the outbreak's first two U.S. deaths, both in Michigan. The California Department of Public Health's message, as reported by KQED in mid-July, was blunt: the state "is not one of the states currently experiencing an increase in cases of cyclosporiasis."

Then California's own numbers moved. The state reported just 41 cyclosporiasis cases from January through June. CDPH data — as reported by KQED on Aug. 7 — showed 215 "confirmed and probable" cases as of July 15, including 13 hospitalizations. The state's 2015–2025 annual average is 106. California logged roughly two years' worth of an average caseload in a matter of weeks, even as it insisted it had dodged the national outbreak.

The figures are less contradictory than they look. Cyclosporiasis is seasonal: the CDC treats May 1 through Aug. 31 as its U.S. season, so a summer climb is expected. The counting bases also differ. CDPH recorded the 41 as provisional early-year cases; the 215 is a cumulative confirmed-and-probable tally reaching through mid-July. What the state cannot yet explain is why the summer numbers are running hot.

CDPH's public cyclospora dashboard describes the pattern as "a normal seasonal pattern and mostly associated with travel to other countries." In a statement it provided to KQED, the agency also acknowledged that "our cases are now higher than what we might expect for this point in the season, based on historical data," and said it is "still investigating cases and the cause of the increase."

The department's working theory points away from California produce and toward the airport. Of 201 cases reported since May 1, CDPH said only 39 were "domestically acquired" — and 15 of those people had traveled to other states. The majority, the agency said, were tied to international travel to regions where cyclosporiasis outbreaks are underway. The agency also suspects "increased cases in travelers to areas with cyclosporiasis outbreaks, whether international or domestic."

Dr. Peter Chin-Hong, an infectious disease expert at UCSF, framed the surge as a function of scale and mobility rather than a local food-safety emergency. "California is a relatively large population, a lot of people travel," he told KQED. Wherever a Californian picked up the parasite, he said, "it's all about where people are infected in terms of being worried versus the numbers, even if the numbers continue to go up."

CDPH also pointed to testing itself. The agency said heightened attention to the illness has "likely led to increased testing for the illness," which could mean California is identifying more cases than in previous years rather than experiencing a true spike in infections.

For salad-eaters, the practical upshot is unglamorous but reassuring. The parasite is foodborne, not casually contagious person-to-person, and CDPH's standard advice holds: wash produce under running water, discard outer lettuce leaves, and be cautious with food and water when traveling abroad. The bigger caveat is epidemiological honesty — California is telling residents both that everything is within a normal seasonal range and that it doesn't yet know why the numbers are this high.