Health officials are investigating a growing outbreak of Cyclospora, a foodborne parasite that can cause severe gastrointestinal illness, after cases climbed sharply in Michigan and continued to rise in several other states.

Michigan has been hit hardest, with the state Department of Health and Human Services reporting 572 confirmed cases of cyclosporiasis over the weekend, up from 170 reported just days earlier.

Federal data also show infections in Ohio, North Carolina, Wisconsin, Texas, and more than a dozen other states.

Ohio has reported 177 cases as of July 2, while North Carolina has confirmed 110, according to each state's data.

Investigators have not yet identified the source of the outbreak.

"ODH and local health departments are working with neighboring state partners, including Michigan, and federal partners to investigate," Ohio Department of Health spokesman Ken Gordon said in a statement shared with The Columbus Dispatch.

"This includes conducting interviews to help identify any potential common exposures," Gordon said. "At this point, no source has been confirmed."

Health officials say people become infected after consuming food or water contaminated with the Cyclospora parasite. Previous outbreaks have been linked to bagged salad mixes, fresh herbs, snow peas, green onions, and raspberries.

According to the Centers for Disease Control and Prevention, symptoms typically appear two days to two weeks after exposure and often include watery diarrhea, stomach cramps, bloating, nausea, fatigue, loss of appetite, weight loss, and increased gas. Some patients also develop vomiting, headaches, body aches, and low-grade fever.

Without treatment, the illness can linger for more than a month, with symptoms sometimes disappearing and then returning. Older adults and people with weakened immune systems face a higher risk of serious complications.

Doctors diagnose the illness through stool testing and generally treat it with sulfa-based antibiotics such as Bactrim, Septra, or Cotrim. Health experts also stress the importance of replacing fluids to prevent dehydration.

"What leads people to the emergency room is the complication of profound dehydration that comes as a result of this," ABC News medical contributor Dr. Darien Sutton said Monday on Good Morning America.

CDC data released July 1 show at least 20 hospitalizations linked to Cyclospora infections this year. No deaths have been reported.

"These people became sick after eating food in the United States and did not report any travel during the 14 days before they got sick," the CDC said, according to the Independent.

While the agency said there is no evidence of a single nationwide outbreak, it added that state, local and federal health officials are investigating "several clusters of cases in more than one state."