The Mohonk Mountain House, on the shore of a half-mile-long lake in New Paltz, N.Y., 90 miles north of New York City, closed a week after guests at the National Historic Landmark started complaining of a stomach virus, Marketing Director Nina Smiley told United Press International.
The virus also affected staff members.
"Preliminary information indicates that the illness is consistent with norovirus," state Department of Health spokesman Jeffrey Hammond told UPI in a statement.
The department is investigating the outbreak with the local Ulster County Department of Health to verify the source of the illness, he said.
The norovirus causes severe stomach pain, nausea, diarrhea and vomiting.
It is the most common cause of gastroenteritis, or the "stomach bug," in the United States, infecting 1 in every 15 Americans a year, the federal Centers for Disease Control and Prevention says.
It is "not considered serious for the general population," Hammond said.
People typically contract it by eating virus-contaminated foods, drinking infected liquids, touching contaminated surfaces or having direct contact with an infected person, the CDC says.
Mohonk is undergoing a deep cleaning and sanitization process, Smiley told UPI.
Disaster-remediation company BMS Cat Inc. of Fort Worth, Texas, "sent their team -- 200 people working around the clock on this," she said.
Mohonk's management expects to reopen the 145-year-old castle-like resort Feb. 14, in time for the Valentine's Day weekend, Smiley said.
The 259-room hotel, which can accommodate 600 guests, has "never closed before," Smiley said.
"There are viruses going around and one happened to hit Mohonk," she told UPI, adding, "We're just looking forward to being back to business as usual."