A group of researchers led by a team from the University of Virginia Health System found that adults infected with rhinovirus, the cause of half of all colds, may contaminate many objects used in daily life, leaving an infectious gift for others who follow them.
Most are aware that handshaking and other forms of skin to skin contact can result in catching someone else's cold, but many may assume that viruses can't live long on hard surfaces in living environments. Dr. Owen Hendley, professor of pediatrics in the Division of Pediatric Infectious Diseases at the UVa Health System who will present the research, cautions that this assumption may not be completely true.
"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 Hendley.
To begin the study, people with colds were recruited to spend 5 hours awake in hotel rooms before going to bed and 2 awake hours in their rooms the next morning. The volunteers had no visitors and were asked to wash their hands only after using the bathroom. At the time of check out, participants were asked to identify objects they had touched. After they left, ten of the touched objects in the subject's room were tested for the presence of rhinovirus. Thirty five percent of the objects had residual virus, demonstrating that people with colds do not have to be present for their germs to linger.
In order to infect an individual, germs must reach the eyes or the nose, usually by way of a person's own fingers. So researchers then set out to learn if germs lingering in the environment can make the leap from surfaces to fingers.
In order to test this leap, researchers invited six of the participants to return to the hotel several months later. This time, virus-containing mucus taken at the time of the participants' colds, which had been stored, was used to contaminate two sets of light switches, telephone key pads and telephone handsets in two different rooms. In one room, the mucus was allowed to dry for one hour. In the second room, the mucus dried overnight. The participants were asked to dial phone numbers, hold the handsets and flip on light switches in both rooms. Sixty percent of the contacts with contaminated objects that dried for an hour resulted in rhinovirus transfer to fingertips. Thirty-three percent of contacts with objects that dried overnight resulted in rhinovirus transfer to fingertips.
Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect rhinovirus ribonucleic acid (RNA). The RNA of rhinovirus is surrounded by proteins that help it bind to other cells. Without a host cell, the virus cannot replicate, making it even more surprising that it survived overnight to be detected and transferred.
"While transmission of rhinovirus through dried nasal mucus on surfaces is not efficient, people still should understand that the virus remains available for transfer at least one day," said Hendley. "The next time you stay in a hotel, knowing that rhinovirus may be left from the last guest, you may wonder how meticulous the clean up crew was in their work."