Researchers at a new meeting of the American Society for Microbiology revealed some icky information: It takes only two to four hours for a virus to spread to an entire building. A research team, presenting its material at the 54th Interscience Conference on Antimicrobial Agents and Chemotherapy that took place today, September 8, showed that within a couple of hours a test virus could spread to about 40 to 60 percent of a heavily trafficked building. The team tested work office buildings, hotels and health care buildings such as hospitals.

However, just because a virus can spread so quickly through a building doesn't mean that there isn't anything we can do to escape infection. Simple actions can be effective protection against disease.

"Using disinfecting wipes containing quaternary ammonium compounds (QUATS) registered by EPA as effective against viruses like norovirus and flu, along with hand hygiene, reduced virus spread by 80 to 99 percent," says Charles Gerba, the researcher who gave the presentation of the study's results.

Every year, norovirus causes somewhere between 19 and 21 million infections in the United States, resulting in 570 to 800 deaths a year. The new study used a tracer virus - a virus that closely resembles a harmful norovirus but is actually harmless - called bacteriophage MS-2, to test how norovirus spreads in buildings. The researchers planted the virus on a couple of surfaces in office buildings and one health care building, and tracked the spread of the virus through the building over the next eight hours, periodically collecting samples from different sites around the building and testing them for the virus. They focused on commonly touched surfaces like table tops, buttons and door knobs.

The team found that by 2 to 4 hours after the virus was planted, it had spread to about 40 to 60 percent of the sites tested in the buildings.

The cleaning personnel then distributed disinfectant wipes to people in the building and told them how to use them correctly to reduce spread of the virus. When the team tested afterwards, it found that the use of disinfectants reduced the concentration of the virus by at least 99 percent.

"The results shown that viral contamination of fomites in facilities occurs quickly, and that a simple intervention can greatly help to reduce exposure to viruses," says Gerba.