The Town of Lexington warned residents on Wednesday, July 8, about a stomach parasite that has sickened at least 18 people in Massachusetts since May 1, part of a national outbreak federal health officials expect to last through August.
Cyclosporiasis, caused by the microscopic parasite Cyclospora cayetanensis, infects the small intestine and spreads through food or water contaminated with infected feces. It does not spread person to person. The Massachusetts Department of Public Health (MDPH) reported the 18 confirmed state cases in an advisory the town posted to lexingtonma.gov.
The national picture is far worse. As of Monday, July 13, the CDC had confirmed 1,645 cases across 34 states, with 141 hospitalizations and zero deaths. More than 5,100 additional suspected cases await lab confirmation. Michigan has been hardest hit, with more than 3,700 confirmed and suspected cases reported as of July 15. Health officials there have pointed to lettuce and bagged salad greens as a "potential source," though no definitive cause has been confirmed nationwide.
"We're seeing an unusually high number of cyclosporiasis cases this summer," Gwen Biggerstaff, deputy director of the CDC's Division of Foodborne, Waterborne, and Environmental Diseases, said at a media briefing on Tuesday, July 14.
Massachusetts may be spared the worst. Dr. Zoe Weiss, an infectious disease specialist at Tufts Medical Center, told WCVB on Tuesday, July 15, that the state's 18 cases are consistent with normal seasonal levels and that Massachusetts is unlikely to see the surge hitting the Midwest. The 18-case figure dates to the July 8 advisory and may have since changed.
Symptoms include watery or "explosive" diarrhea, bloating, nausea, vomiting, fatigue, stomach cramps, and weight loss. The incubation period is typically about one week but can range from two days to more than two weeks. If untreated, the illness can last more than a month, with symptoms that come and go.
People who have contracted the illness in the current outbreak range in age from 15 to 89, with a median age of 46, according to the CDC.
MDPH recommends:
- Wash all fruits and vegetables thoroughly under clean running water.
- Scrub firm produce like melons and cucumbers with a produce brush.
- Cook produce to 158 degrees Fahrenheit or higher, which kills the parasite.
Previous U.S. outbreaks have been linked to raspberries, bagged lettuce, cilantro, fresh basil, snow peas, and green onions.
Anyone who suspects they have cyclosporiasis should see a doctor. The illness is treatable with antibiotics. The CDC notes that standard stool tests may not detect Cyclospora, so patients should specifically ask their provider to test for the parasite.
Health officials advise people with diarrhea to rest and drink plenty of clear fluids. Residents can find updates from the Massachusetts Department of Public Health at mass.gov/dph.
