More than 160 people have now become ill from a multistate outbreak of parasitic illness traced to McDonald’s salads, federal health officials say.

The Centers for Disease Control and Prevention said Thursday that 163 people across 10 states have been sickened by the cyclospora parasite after eating McDonald’s salads, which were pulled last week from about 3,000 locations across the country.

Officials with the fast-food chain said in a statement that the growing number of states reported by the CDC and the U.S. Food and Drug Administration are among the same states where “we proactively decided to remove our lettuce blend in impacted restaurants and replace it through a different supplier.” Previously, public health authorities in Illinois and Iowa had warned that a number of recent cyclospora infections in those states appear to be connected to the salads.

The CDC said in a statement that because McDonald’s proactively pulled the salads in numerous states, “there likely is not ongoing risk to consumers who eat at those McDonald’s locations.”

Cyclospora cayetanensis is a parasite that can contaminate food and water through feces. When ingested, it can cause a non-life-threatening intestinal illness called cyclosporiasis, and symptoms of the illness typically appear about a week after infection, according to the CDC.

Since May, hundreds of cases of infection have been reported in the United States.

In June, Del Monte, which distributes fruits and vegetables, recalled prepackaged Del Monte Fresh Produce vegetable trays, which contained broccoli, carrots, cauliflower, celery sticks and dill dip, from certain retailers, including Kwik Trip and Peapod, according to the CDC. Residents in four states — Iowa, Michigan, Minnesota and Wisconsin — were reported to be sickened by the parasite.

The CDC said last week there were 227 laboratory-confirmed cases in which people became ill from the parasite after eating the produce. That number has since increased to 237, according to the agency.

At the same time, public health authorities in Illinois and Iowa reported that a number of cases there had been linked to the salads at McDonald’s and the CDC said it had received reports from numerous other states. The announcements prompted the chain to pull salads from stores in Illinois, Indiana, Iowa, Kentucky, Michigan, Minnesota, Missouri, Montana, Nebraska, North Dakota, Ohio, South Dakota, West Virginia and Wisconsin, it said.

Officials with the Illinois Department of Public Health (IDPH) said in a statement that about 90 cases of cyclosporiasis had been reported across the state — and about 25 percent of those sickened said they had eaten the salads days before the onset.

In Iowa, public health authorities reported similar findings.

“This summer there have been several clusters of Cyclospora illness associated with various foods that are commercially available. This week [the Iowa Department of Public Health] has identified 15 Iowans who ate McDonald’s salads in late June to early July prior to getting ill,” Patricia Quinlisk, medical director of the state health department, said in a statement. “Anyone who ate these salads since the middle of June and who developed diarrhea, especially watery diarrhea and fatigue, should see their health care provider and get tested for Cyclospora to ensure an accurate diagnosis and appropriate treatment.”

Recently, a string of food-borne illnesses have been reported across the United States. Salmonella illness outbreaks have been linked to raw turkeypasta saladKellogg’s Honey Smacks cereal and pre-cut melonRomaine lettuce was determined to be contaminated with E. coli. Fresh crab meat from Venezuela was deemed a risk after Vibrio parahaemolyticus sickened a dozen people in three states and Washington, D.C.

Bill Marler, a food safety attorney, said the reason that outbreaks seem to be occurring more frequently is likely a combination of better detection as well as an increase in the cases themselves.

“It seems that there’s something more going on in the food system than just better surveillance,” he told The Washington Post.

Regarding cyclosporiasis, the CDC said symptoms may include:

  • Watery diarrhea
  • Nausea and loss of appetite
  • Gas, bloating and stomach cramps

In some cases, people may also experience fever and vomiting, it said.

People often recover without medical intervention, according to the CDC, but antibiotics are also used to treat the condition.

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