The number of people with parasitic infections in an ongoing outbreak continues to increase, with 40 more added in the past week. The tally stands at 476 now in the outbreak traced to salad mix distributed by Fresh Express and sold by some McDonald’s restaurants.

Since the initial outbreak announcement on July 13, there has been a 680 percent increase in the case count, which started at 61. 

Of the 476 patients now confirmed, at least 21 have been so sick from the microscopic Cyclospora parasites that they were admitted to hospitals, according to an update yesterday from the Centers for Disease Control and Prevention. The agency has not received any reports of confirmed deaths in the 15-state outbreak.

Although McDonald’s stopped serving the implicated salads in more than 3,000 restaurants on July 13, public health officials say they expect more people to be confirmed with infections. It can take up to six weeks after consuming the parasite before people develop symptoms of cyclosporiasis.

The known dates of illness onset range from May 20 to July 20. Ill people range in age from 14 to 91 years old. However, the CDC qualified those dates and ages, reporting that people who became ill after July 5 could easily not yet be included in the overall case count.

Investigators with the Food and Drug Administration continue to investigate what specific food was contaminated with the microscopic parasites. Officials with the fresh produce supplier, Fresh Express, told the FDA that some of its business customers other than McDonald’s received salad mixes with some common ingredients. But, the produce corporation reported McDonald’s was the only entity to receive salad mix that contained carrots. 

More than 3,000 McDonald’s locations in 14 states received the salad mix. Those states are Illinois, Indiana, Iowa, Kentucky, Michigan, Minnesota, Missouri, Montana, Nebraska, North Dakota, Ohio, South Dakota, West Virginia and Wisconsin, according to the FDA. The company reported it replaced the supplier of the salads in those states. Illinois has been hardest by far, with 246 of the confirmed patients.

State Number of Cases
CT* 1
FL* 1
IA 98
IL 246
IN 8
KY 8
MI 2
MN 10
MO 52
NE 5
OH 15
SD 18
TN* 1
VA* 1
WI 10

*Note, the Connecticut, Tennessee, and Virginia case-patients purchased salads while traveling in Illinois; the Florida case-patient purchased a salad while traveling in Kentucky.

Advice to consumers
Anyone who has eaten a McDonald’s salad and developed symptoms of cyclosporiasis should seek medical attention and tell their doctors about their possible exposure to Cyclospora parasites.

Symptoms usually include diarrhea, with frequent, sometimes explosive, bowel movements. Other common symptoms include loss of appetite, weight loss, stomach cramps/pain, bloating, increased gas, nausea, and fatigue. Vomiting, body aches, headache, fever, and other flu-like symptoms may be noted.

Some people who are infected with Cyclospora parasites do not have any symptoms. If not treated, the illness may last from a few days to a month or longer. Symptoms may seem to go away and then return one or more times, making diagnosis difficult.

“The Cyclospora parasite needs time — days to weeks — after being passed in a bowel movement to become infectious for another person,” according to the Food and Drug Administration. “Therefore, it is unlikely that cyclosporiasis is passed directly from one person to another.”

Cyclospora parasites can contaminate foods or beverages, but in the United States they are most often found on fresh produce, according to federal officials.

(To sign up for a free subscription to Food Safety News, click here.)