A foodborne parasite has been wreaking havoc on people in Massachusetts — with more than 100 cases being reported since May, according to health officials.

The microscopic culprit, Cyclospora, had only caused an average of 18 to 33 infections per year since 2016 before the most recent spike.

“Most cases this year have occurred in greater Boston, but infections have been reported in residents across the Commonwealth,” said the Massachusetts Department of Health in a press release this week.

“Other states have also reported increases in the number of cyclosporiasis cases,” the department added. “The cause of the outbreak is not yet known.”

Health officials began tallying the number of Cyclospora cases in May and found that there had been over 100 of them in Massachusetts, alone. At least 10 other states have reported infections during this same timespan — including New York.

Cyclospora can ultimately cause Cyclosporiasis, a disease described by the Centers for Disease Control and Prevention as “an intestinal illness” that can be contracted “by consuming food or water contaminated with the parasite.”

“Individual cases are usually associated with travel to warmer countries where the parasite is more common. However, only a small number of the recent Massachusetts cases have been tied to international travel,” the health department said. “Historically, outbreaks of this illness in the US and Canada have been linked to imported fresh produce including Guatemalan raspberries and snow peas (2000 and 2004); Thai basil (2001); Mexican bagged salad mix (2013); and prepackaged commercial fresh vegetable trays (2018). Outbreaks involving restaurants have also been reported. At this time, no particular food item has been linked to the cases of Cyclospora infection occurring this year in Massachusetts.”

Public Health Commissioner Monica Bharel, who is quoted in the health department’s release, said individuals who contract the parasite usually become symptomatic about a week after eating contaminated food.

“Symptoms typically include watery diarrhea, loss of appetite, abdominal cramping, nausea, and prolonged fatigue,” Bharel added. “Immunocompromised people may have more prolonged symptoms. Many infections will resolve on their own, but people with symptoms should seek medical care as the infection is best treated with an antibiotic prescribed by a healthcare provider. “

The health department has been working with local Boards of Health, officials in other states, the CDC and the FDA to trace the cause of the alarming outbreak.

“This illness is not spread person-to-person like many other food-borne diseases, like salmonella or E.coli,” explained Dr. Larry Madoff, medical director of the department’s Bureau of INfectious Disease and Laboratory Sciences.

“When a specific contaminated food item is identified, prevention involves removing that product from distribution,” he said. “In the absence of a specific food item linked to the outbreak, prevention, in this case, means using safe food handling practices. ”

To best prevent infection and all foodborne illnesses, residents and retailers have been asked to follow safe fruit and vegetable handling recommendations — including washing hands with soap and warm water and keeping items refrigerated.