FRIENDSVILLE, Md. (AP) — Maryland public health officials are investigating the cause of nausea and vomiting that struck high school students aboard a bus returning to Uniontown, Pa., from Washington, D.C. over the weekend.

Garrett County Health Officer Rodney Glotfelty said Monday that 13 students were taken to area hospitals after the bus chartered by the Albert Gallatin School District stopped Saturday evening in Friendsville. None of the students was admitted for hospital care.

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Goltfelty says their symptoms point toward a food-borne or water-borne illness, or a gastrointestinal virus. He says the investigation will involve public health agencies in numerous jurisdictions.

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The Cumberland Times-News reports that emergency responders ruled out carbon monoxide poisoning.

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