(CNN) -- Prepackaged salad mix has been pinpointed as the source of an outbreak of cyclospora -- an intestinal illness tied to a rare type of parasite -- that has sickened scores of people in Iowa and Nebraska, health authorities in those states said Tuesday.
More than 100 Iowans and 78 Nebraskans have fallen ill with the disease since last month, those states' health departments said. Five people have been hospitalized as a result in Nebraska, where health officials say new cases of cyclospora are reported daily.
Investigations commonly led authorities in both states to conclude that a bagged blend of iceberg and romaine lettuce, red cabbage and carrots is to blame, with Nebraska noting the mix had been prewashed.
State and federal authorities are still trying to determine exactly where the product was sold or under what brand name. The Nebraska alert noted that it "came through national distribution channels" and that "locally grown produce is not part of this outbreak."
Iowa authorities found that about 80% of those who fell ill had prepackaged salad, but the allegedly tainted product was apparently no longer on grocers' shelves by the time investigators were alerted.
The upside of this delay? "Iowans should continue eating salads as the implicated prepackaged salad mix is no longer in the state's food supply chain," said Steven Mandernach, the head of that state's food and consumer safety bureau.
What's happening in Iowa and Nebraska may be linked to 122 cyclospora cases in Texas, that state's department of health services said. As of Tuesday, authorities had not singled out a common source for the Lone Star State's outbreak, which is largely centered in and around Dallas and Fort Worth.
The U.S. Centers of Disease Control and Prevention has been collaborating with health officials in numerous states since late June trying to pin down what's causing the spate of cyclospora cases.
People get the disease by eating food or drinking water that's been contaminated with feces with the parasite, according to the CDC. The ailment -- which strike in places where cyclospora is common, like tropical or subtropical regions, but is occasionally seen in the United States as well -- causes symptoms such as diarrhea, weight loss and nausea that can last anywhere from a few days to more than a month.