Concord's Health Division said no cases of cyclosporiasis have been reported in town, even as health officials monitor a nationwide surge tied to contaminated fresh produce.

The update, issued July 16, comes as the Centers for Disease Control and Prevention investigates one of the largest Cyclospora outbreaks in recent years. Since May 1, the CDC has confirmed 1,645 cases across 34 states, sending 141 people to the hospital. No deaths have been reported.

Massachusetts had recorded 18 cases as of July 1, according to the state Department of Public Health, which says it has not identified any unusual spike or common source within the state.

What's causing the outbreak?

Cyclosporiasis is caused by the microscopic Cyclospora parasite, which spreads through contaminated food or water—not from person to person.

Most infections have historically been linked to fresh produce, including leafy greens, berries, bagged salads, basil and cilantro.

On July 17, the CDC identified shredded iceberg lettuce served at Taco Bell restaurants in parts of the Midwest as one source of the current outbreak. The lettuce was traced to a single supplier, and Taco Bell has since stopped using it.

No New England states have been connected to that investigation.

What are the symptoms?

Symptoms usually appear about a week after eating contaminated food and can include:

  • Watery diarrhea
  • Nausea
  • Loss of appetite
  • Bloating
  • Fatigue
  • Weight loss

Without treatment, the illness can last for weeks. Doctors typically treat it with antibiotics.

How to protect yourself

Concord health officials recommend thoroughly washing fresh fruits and vegetables and scrubbing firm produce, such as melons and cucumbers, before eating.

Anyone with prolonged diarrhea should contact a healthcare provider and ask about Cyclospora testing, since routine stool tests don't always detect the parasite.

While there are no reported cases in Concord, public health officials say the nationwide outbreak is a reminder to take extra care when preparing fresh produce during the summer months.