As cyclospora illnesses surge to a record, Michigan officials eye
lettuce as a possible cause
[July 15, 2026]
By MIKE STOBBE
NEW YORK (AP) — Infections from the diarrhea-causing parasite cyclospora
are surging, with state-level data suggesting that 2026 is already the
nation's worst year for reported cases.
More than 30 states have reported infections this year, and current data
from them shows the number of infections surpassing the record U.S. mark
of about 4,700 set in 2019. The illness is not usually life threatening
and is typically treated with antibiotics.
Health officials have not yet definitively identified what is causing
the infections. On Tuesday, federal health officials said there may be
different infection patterns in different places, although they believe
cases in at least four states — Michigan, Ohio, Kentucky and West
Virginia — are linked.
Michigan officials blame lettuce
In Michigan — where more than 3,300 cases have been reported — officials
say early information points to lettuce or salad greens as a possible
culprit.
After conducting more than 1,000 interviews with patients, “early
information has shown lettuce as a common product that regularly comes
up during the investigation,” said Natasha Bagdasarian, the Michigan
health department's chief medical executive.
Because of that commonality and because produce has been behind some
past cyclospora outbreaks, Michigan officials advised consumers to buy
whole heads of lettuce, discard the outer layers and thoroughly wash
what is left. They also suggested people avoid bagged lettuce and
pre-mixed salad kits.
On Tuesday, the Taco Bell restaurant chain issued a statement saying it
had “voluntarily and temporarily removed limited ingredients at select
restaurants as a precautionary measure. We will continue to closely
monitor the situation and follow the guidance of public health
authorities."
In a call with reporters on Tuesday, federal health officials did not
directly respond to a question about whether they are looking at Taco
Bell or any specific food vendor or distributor.
“FDA certainly is continuing its traceback investigation on multiple
produce items, also including locations that are reported by the case
patients before they became sick,” said Donald Prater, The U.S. Food and
Drug Administration's Acting Deputy Commissioner for Food, in response.
Cyclospora causes ‘explosive’ diarrhea
Cyclospora is a microscopic, spherical parasite that commonly causes
watery diarrhea “with frequent and sometimes explosive bowel movements,”
according to the U.S. Centers for Disease Control and Prevention.
Outbreaks tend to occur most often in the late spring and summer.
The heat-loving parasite infects the bowels and spreads through feces.
In the past, people have been infected by consuming fruits or vegetables
that were exposed to feces-contaminated irrigation water.
The illness, called cyclosporiasis, is less common than foodborne
illnesses caused by other germs, including salmonella and E. coli. Many
cases are never linked to a specific food or other source and, for
years, few U.S. cyclospora outbreaks were reported. But the number
started rising about a decade ago, with a particularly notable spike in
2018 and 2019.
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This undated photo taken through a microscope provided by the CDC
shows Cyclospora cayetanensis oocysts found in a fresh stool sample
which had been prepared with a formalin solution and stained with
safranin. (CDC via AP)
 Experts say it's likely that
cyclospora cases historically were underreported, in part because
some common tests used to check for food poisoning have not been
geared to detect cyclospora. They attribute the increasing trend in
cases to climate change and better detection.
2019 was the worst year for infections
The worst year in the U.S. for infections was 2019, when about 4,700
illnesses were reported, according to federal data on confirmed and
suspected cases.
The Centers for Disease Control and Prevention keeps those numbers,
but they traditionally lag what is posted by individual city and
state health departments dealing with local outbreaks in real time.
On Tuesday, CDC officials issued a health alert that said that since
May 1, the agency is aware of 1,645 confirmed domestic cases and
more than 5,100 that require further analysis to confirm whether the
infections were acquired in the U.S. The reports come from 34
states, and no deaths have been reported, the CDC said.
The true number of cases is likely larger than what has been
reported so far because some people may have milder illnesses that
they don't seek care for, said Gwen Biggerstaff, deputy director of
CDC’s Division of Foodborne, Waterborne, and Environmental Diseases,
in the call with reporters.
It can take days to weeks for someone exposed to the parasite to
develop symptoms. It's not clear to what extent people currently are
being infected, or whether many of the exposures happened earlier.
But Biggerstaff said official expect that case numbers will continue
to grow through August.
The CDC also posted information about the investigation of an
outbreak affecting the four states.
The federal alert did not detail how many reports came from each
state. But Michigan officials have reported more than 3,300 cases,
officials in northwest Ohio said they have seen more than 1,100, New
York City officials counted more than 400 and Illinois reported more
than 200.
Officials do not think all can be tied to a common source. In
Illinois, for example, more than half the people with infections
said they had traveled outside the United States, and at least some
may have been infected elsewhere.
But Michigan officials believe a large share of their total is
likely due to a linked domestic outbreak. CDC officials did not go
into detail about why they currently think cases in Michigan, Ohio,
Kentucky and West Virginia are part of the same outbreak.
___
Associated Press writer Dee-Ann Durbin in Detroit contributed to
this report.
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