Cyclospora Outbreak Spreads Across U.S. as Federal Officials Trace Major Cluster to Mexican Lettuce

A sharp increase in illnesses caused by a microscopic intestinal parasite has spread across much of the United States, prompting federal health officials to warn doctors and consumers about prolonged symptoms that can last for weeks without treatment.

The U.S. Centers for Disease Control and Prevention reported 1,645 confirmed domestically acquired cases of cyclosporiasis across 34 states as of July 14. Another 5,100 cases were awaiting further analysis to determine whether they were acquired inside the United States.

At least 141 patients have been hospitalized, while no deaths have been reported. By comparison, only 249 confirmed cases had been reported nationally during the same period last year.

Michigan has recorded the greatest number of illnesses, with state officials tracking thousands of confirmed and probable infections.

Federal investigators are examining several clusters and potential food sources. One major outbreak has been traced to shredded iceberg lettuce supplied by Taylor Farms de Mexico and served at Taco Bell restaurants in Michigan, Indiana, Ohio, Kentucky and West Virginia.

The Food and Drug Administration said 1,644 illnesses and 94 hospitalizations were connected to that five-state outbreak. Approximately 90 percent of patients interviewed about what they ate reported consuming iceberg lettuce.

On Friday, Taylor Farms de Mexico announced that it was voluntarily removing all iceberg lettuce sourced from central Mexico from the U.S. market and told the FDA that it would initiate a recall.

The FDA warned consumers not to eat shredded iceberg lettuce from the supplier served at Taco Bell locations in the five affected states. Not every Taco Bell restaurant in those states received the implicated product, and federal officials said additional restaurants, retailers or distribution channels could be identified as the investigation continues.

Two Cases Reported in Maine

Maine has reported two cases of cyclosporiasis so far this year, but state health officials have said neither case has been linked to the national outbreak investigation.

“Neither are linked to the ongoing national outbreak investigation, nor has a specific food source been linked to these cases,” Maine CDC spokesperson Lindsay Hammes said earlier this week.

There is also no indication that the shredded lettuce implicated in the five-state Taco Bell outbreak was served at Maine restaurants.

Still, the national surge has affected Mainers by raising concerns about bagged salads, restaurant lettuce and other fresh produce that can carry the parasite. Federal officials have warned that the number of cases will likely continue increasing through the end of the summer, when Cyclospora infections are most commonly reported.

Cyclosporiasis cases generally rise between May and August. In past decades, infections were often associated with international travel, but federal health officials have increasingly linked domestic cases to contaminated food sold or served in the United States.

What Is Cyclospora?

Cyclosporiasis is an intestinal illness caused by the parasite Cyclospora cayetanensis. People are generally infected after eating food or drinking water contaminated with the parasite.

The illness is not usually spread directly from one person to another.

Symptoms typically begin about one week after exposure, although they can appear anywhere from two to 14 days after a person consumes contaminated food or water.

The most common symptom is frequent, watery diarrhea. Other symptoms can include:

• Stomach cramps, bloating and increased gas
• Nausea and loss of appetite
• Weight loss
• Extreme fatigue
• Low-grade fever
• Vomiting, headaches or body aches

Symptoms can disappear and later return. Without treatment, the illness may continue for a month or longer, and severe diarrhea can lead to dehydration. People with weakened immune systems may experience more serious or prolonged complications.

What Consumers Should Know

The CDC recommends washing all fresh fruits and vegetables thoroughly under clean, running water before eating them, including produce labeled as prewashed.

Washing can reduce contamination, but federal health officials cautioned that chemical sanitizers may not completely eliminate Cyclospora from produce. Cooking vegetables will kill the parasite.

Consumers should also wash their hands before preparing food and clean cutting boards, utensils, containers and countertops that come into contact with raw produce.

Fresh herbs, leafy greens, bagged salads and berries have been associated with previous Cyclospora outbreaks, but federal officials have not advised Americans to stop eating all fresh produce.

The current FDA warning is specifically directed at shredded iceberg lettuce from Taylor Farms de Mexico served at Taco Bell locations in Michigan, Indiana, Ohio, Kentucky and West Virginia.

Anyone experiencing prolonged watery diarrhea, particularly symptoms lasting more than a few days, should contact a health care provider. Doctors may need to specifically request testing for Cyclospora because routine stool examinations do not always detect the parasite.

Confirmed infections are generally treated with a seven- to 10-day course of the prescription antibiotic trimethoprim-sulfamethoxazole. Patients are also advised to remain hydrated, particularly when diarrhea is frequent or severe.