(AP) — State health officials are confirming three new cases of rare parasite in Nebraska, bringing the total number to 81.

Nebraska state epidemiologist Dr. Thomas Safranek said his office received confirmation of the new cases on Wednesday. Safranek says he is urging the medical community to stay vigilant for new cases of cyclospora, a parasite that causes lengthy gastrointestinal illness. Outbreaks have been reported in at least 15 states.

A spokeswoman for the Nebraska Department of Health and Human Services says two of the new cases were reported in Sarpy County, and one was reported in Lancaster County.

Nebraska officials say they’ve traced cases to a prepackaged salad mix that includes iceberg and romaine lettuce, along with red cabbage and carrots.