A parasitic infection that causes severe diarrhea has recently appeared in 34 states, including Arizona. But the number of cases in Arizona remains low, and local cases may not be linked to the major outbreak in other states.
The U.S. Centers for Disease Control and Prevention reports more than 1,600 cases of cyclosporiasis have been confirmed in the U.S. since May, and more than 5,000 possible cases remain under investigation. The CDC notes these numbers are likely an undercount.
Michigan has been the state hardest hit by the outbreak. Michigan’s health department has counted more than 5,000 cases and more than 100 hospitalizations from the gastrointestinal infection.
Arizona has reported just 19 cyclosporiasis cases this year — that’s pretty typical, said Dr. Joel Terriquez, division medical director for public health preparedness with the Arizona Department of Health Services.
“It’s not something that is different or unusual or new,” Terriquez said. “It’s something that we see every year and we have not been able to identify an association with the number of cases that we’re seeing in other states.”
Last year, Arizona reported 50 illnesses caused by the cyclospora parasite. In 2024, the state had 22 cases and in 2023 there were 85 cases.
As of last week, Arizona had reported 10 cyclosporiasis cases in 2026. This week, the case count nearly doubled, rising to 19.
But Terriquez said the recent increase in cases in Arizona may just be part of the illness’s normal seasonal pattern — the infection is more common in summer months.
And Terriquez suspects more Arizonans have recently been seeking diagnosis and treatment for gastrointestinal illnesses amid the ongoing coverage of the U.S. cyclosporiasis outbreak.
“The community is looking at it very closely,” Terriquez said. “There might be a little bit of that as the reason we’re identifying more cases over the past week or so.”
Terriquez said the Arizona Department of Health Services is continuing to closely monitor the U.S. outbreak.
“This is something that we look at, but so far there has been no real association with those cases,” Terriquez said.
The CDC has linked the current outbreak to shredded iceberg lettuce served at Taco Bell locations in Indiana, Kentucky, Michigan, Ohio and West Virginia.
According to the CDC, the cyclospora parasite infects the small intestine and can cause severe, watery diarrhea along with fatigue, nausea and stomach pain; though people infected with the parasite may not experience symptoms in all cases. Symptoms may take between two days and two weeks to appear after a person consumes contaminated food or water. Cyclosporiasis is not spread person-to-person. The illness can be treated with antibiotics. If untreated, symptoms may last more than a month.
While the risk of cyclosporiasis remains low in Arizona, Terriquez recommends Arizonans take commonsense steps to avoid all types of foodborne illnesses.
“We want to make sure that we’re washing our hands before and after preparing any meals, we need to make sure that we’re washing all fruit and vegetables thoroughly under running water, we need to refrigerate any cut, peeled and cooked fruits and vegetables as soon as possible,” Terriquez said.
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