Nearly 400 people in 15 states have been sickened by a parasite infection linked to McDonald's salads, according to the Food and Drug Administration.
The outbreak started in May, and the FDA reported an additional 109 cases on Thursday.
MORE: USDA issues health alert about salads, wraps sold at Trader Joe's, Walgreen's, Kroger
At least 16 people have been hospitalized due to the cyclospora parasite, which causes intestinal illness.
Symptoms of the illness include diarrhea, vomiting, fever and body aches.
The illness can last anywhere from several days to a few months and can be treated with antibiotics.
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According to the Food and Drug Administration, an unused package of Fresh Express salad mix tested positive for Cyclospora.
McDonald's said back in July that it had removed the mix from impacted restaurants.
In a statement, Fresh Express said it issued a "Precautionary Recall" on July 27. The Agriculture Department's Food Safety and Inspection Service also issued a health alert about salads and wraps sold at Trader Joe's, Walgreen's and more chains due to possible cyclospora contamination.
Parasite found in McDonald's salads sickens nearly 400 people, FDA says