Researchers at the University of Virginia Health System asked adults infected with rhinovirus, the cause of half of all colds, to stay in hotel rooms, then tested items they touched.

"To my surprise, in a hotel room occupied overnight by an adult with a cold, everything from television remote controls, telephones, light switches and faucets were contaminated with rhinovirus," said Owen Hendley, a professor of pediatrics at the UVa Health System, said is a news release.

To infect a person, germs must reach the eyes or the nose, usually via fingers. To test whether lingering germs can make the leap from surfaces to fingers, six adults later returned to the hotel. Their virus-containing mucus, which had been stored, was used to contaminate light switches and telephones and allowed to dry. They then used the phones and flipped the lights.

From objects that dried for an hour: 60 percent of the contacts transferred rhinovirus to fingertips.

From objects that dried overnight: 33 percent of the contacts transferred rhinovirus to fingertips.

"The virus remains available for transfer at least one day," said Hendley. "The next time you stay in a hotel . . . you may wonder how meticulous the clean up crew was in their work."