Health officials are investigating what has become one of the largest food-borne illness outbreaks in recent years, a multistate surge in cyclosporiasis tied to contaminated shredded iceberg lettuce, but a local infectious disease physician says residents in this area appear to be largely unaffected so far.

Dr. Eric Young, an infectious disease physician for Lehigh Valley Health Network, said he has seen no confirmed cases in the area.

“I personally have not seen any local cases,” Young said. “I know there have been some cases in Pennsylvania, and I can’t say with certainty that we haven’t had any at our hospital, but I’m not aware of any.”

Pennsylvania was formally added to the list of states involved in the Taco Bell-linked outbreak in the most recent Center for Disease Control update, which now counts 1,947 confirmed cases across nine states.

Young said Pennsylvania has between 24 and 28 confirmed cases statewide.

Since May 1, the CDC has received reports of 1,645 laboratory-confirmed domestically acquired cases spanning 34 states — compared to just 249 cases reported during the same period in 2025. Of those confirmed cases, 141 people, or 9%, have been hospitalized. No deaths have been reported. The CDC said it is also aware of more than 11,500 additional cases that are not yet laboratory-confirmed or require further investigation, with many of those additional cases reported in Michigan and Ohio.

The illness is caused by cyclospora, a microscopic parasite.

Dr. Vaishali Patel of St. Luke’s University Health Network said the outbreak has been linked to contaminated shredded iceberg lettuce served at several restaurants.

The main symptoms include fairly severe watery diarrhea, poor appetite and fatigue, with fever possible but not always present. One of the more unusual aspects of the illness is its delayed onset. Patel said it can take up to two weeks after eating contaminated food before a person becomes sick, and without treatment, symptoms can last for weeks.

The outbreak’s primary link is Taylor Farms de México, a produce supplier based in Guanajuato, Mexico. The company voluntarily recalled all iceberg lettuce grown in central Mexico after health officials linked the product to a multistate cyclospora outbreak. The recalled lettuce was distributed between June 29 and July 16 to 27 states, and was sold under several brand names including CV, JB, Mark, PK, SUB, SY, TF and MKTSD, packaged as chopped, shredded and blended lettuce for food service accounts, as well as retail bags in 8-, 12-, 16- and 24-ounce sizes. Pennsylvania is among the states that received the recalled product.

Taylor Farms said it has voluntarily suspended all iceberg lettuce sourcing and production from central Mexico and temporarily halted production of all products at its central Mexico facility as of July 18. The company said it has commissioned independent experts to conduct a full review of food safety processes and protocols at the facility.

Treatment is available

Most cases will not require prescription medication. Young said antibiotic treatment is recommended primarily for people with severe symptoms, those who cannot keep anything down or are becoming dehydrated, as well as those whose symptoms persist for more than a week or who have compromised immune systems, such as patients undergoing chemotherapy or those who have had organ transplants.

“For people who don’t have severe disease, the main thing is going to be staying hydrated, drinking plenty of fluids and getting some electrolytes,” Young said. He added that cautious use of anti-diarrheal medications such as Imodium or Pepto-Bismol can help manage symptoms.

For those who do require an antibiotic, one option stands above the rest. Trimethoprim-sulfamethoxazole, commonly known by the brand name Bactrim, is “really the only antibiotic that’s been found to be reliably effective,” Young said.

Patel urged anyone experiencing persistent diarrhea, especially if symptoms last more than a few days or dehydration becomes a concern, to seek medical attention.

“Effective treatment is available,” she said.

While washing produce is always recommended, Patel cautioned that it may not remove every parasite. Young said cyclospora typically enters the food supply at the farm level.

“It’s excreted by animals that get into the fields, and then there may be issues in terms of the actual washing of the produce,” he said. “It’s almost impossible for this to be spread from person to person. This is not a disease you can catch from somebody,” he said. If multiple members of a household fall ill, he said, it is almost certainly because they all consumed the same contaminated food.

End possibly in sight

The region is not at elevated risk, Young said, and the outbreak may be winding down. With the recall having gone into effect on July 17, the area may be approaching the far end of the parasite’s incubation window.

“The incubation period of this disease can be on the long side — it’s typically a week, but the range is anywhere between two and 14 days,” Young said. “We’re probably getting near the end of this.”

Residents should not expect a lab test to be a routine part of their care. Testing for cyclospora is not commonly available in outpatient settings, the results can be imperfect and the cost can be significant. The CDC has also noted that the parasite is not routinely detected by standard stool testing panels, and has urged clinicians to specifically request testing for cyclospora when it is clinically suspected.

“When we send the test out, it’s often not covered by health insurance, and the bill can be very substantial,” Young said.

As a result, Pennsylvania’s confirmed case count likely represents only a fraction of the actual total.

“We think it’s probably underreported — it’s even nationally underreported because it’s not routinely tested for,” Young said.

The CDC has noted that the number of cyclosporiasis cases being reported nationally is “unusually high” for this time of year. The U.S. reported 2,700 cyclosporiasis cases in all of 2025; the country has already far surpassed that figure in 2026.

For now, both physicians said the most important steps residents can take are washing fresh fruits and vegetables, practicing good hand hygiene and monitoring for symptoms that worsen or persist. Consumers who purchased any recalled iceberg lettuce products should discard them immediately.