- The CDC reported 1,645 confirmed domestic cases of cyclosporiasis, with over 5,000 more awaiting confirmation; Michigan leads with over 3,000 cases.
- The California Department of Public Health (CDPH) says California “is not one of the states currently experiencing an increase” and has reported 41 provisional cases from January to June 2026, down from 80 in the same period of 2025.
- Most 2026 California cases are associated with recent international travel, and since May 1, only four domestically acquired cases have been reported by CDPH, two linked to the Midwest.
- CDPH states there are “no known local outbreaks in California” and no cases linked to multistate outbreaks; the CDC map shows “1-10” cases in the state.
- In the Bay Area, diarrhea is far more likely caused by norovirus or rotavirus, detected in over 99% of wastewater samples from Stanford’s WastewaterSCAN in recent weeks.
Cyclosporiasis cases are surging in the U.S., with the CDC reporting 1,645 confirmed cases and over 5,000 pending, primarily in Michigan, which has seen over 3,000 cases. In contrast, California has reported 41 provisional cases in 2026, down from 80 in 2025.1234
The California Department of Public Health (CDPH) noted that most cases in 2026 are linked to international travel. Since May 1, only four cases in California were contracted domestically, with two linked to the Midwest. The source of the outbreak remains unidentified, although health officials suspect lettuce or salad greens may be involved in Michigan's surge.56
Symptoms of cyclosporiasis, which can take one to two weeks to appear, include watery diarrhea, loss of appetite, weight loss, bloating, stomach cramps, increased gas, nausea, and fatigue. Unlike norovirus, which resolves on its own, cyclosporiasis requires antibiotic treatment to alleviate symptoms. Currently, the Bay Area is experiencing a higher prevalence of other gastrointestinal diseases, with Norovirus and Rotavirus detected in over 99% of wastewater samples.910
According to CDPH, “there are no known local outbreaks in California, and no California cases are currently known to be linked to multistate outbreaks under investigation by the CDC.”
“The CDC has received reports of 1,645 confirmed cyclosporiasis cases domestically, with over 5,000 more awaiting confirmation; Michigan leads with over 3,000 cases. In contrast, California has reported only 41 provisional cases this year, down from 80 in 2025, and no local outbreaks have been identified.”
