Health officials warned this week that an unusually high number of patients in Los Angeles County have been infected with a parasite that causes a severe stomach illness and can last for months if not treated.
Between June and Aug. 1 this year, 14 people in the county had been diagnosed with the intestinal infection cyclosporiasis, according to local health officials.
People typically get sick when they drink water or eat fresh produce that has been contaminated with feces containing the parasite Cyclospora cayetanensis.
Health officials said they did not know what had caused the recent cases, but previous cyclospora outbreaks in the U.S. have been linked to raspberries, basil, cilantro and snow peas.
There were seven cyclospora cases in L.A. County in 2016, zero in 2015 and two in 2014, according to the health department.
Cyclosporiasis is also on the rise nationwide.
Two-hundred and six people in 27 states were infected with cyclosporiasis between May and Aug. 2 this year, compared with 88 nationwide during the same time period last year, according to the U.S. Centers for Disease Control and Prevention. Eighteen people have ended up in the hospital this year.
Patients usually start having symptoms, which can include diarrhea, vomiting, weight loss and nausea, about seven days after ingesting the parasite. Patients require antibiotics to recover.
Health officials said that washing fruits and vegetables with water and a brush could reduce the risk of cyclosporiasis. Careful, regular hand-washing before handling food and after using the bathroom is also important. The parasite, which cannot be seen with the naked eye, cannot be passed from person to person.
National officials said they were unsure of the source of the infections or whether the cases were related.
Laboratories typically don't look for Cyclospora cayetanensis, so health officials reminded doctors to request testing for it if patients reported prolonged diarrhea.