Viruses spread easily from a single doorknob

Posted Sep 12, 2014 by Tim Sandle
Scientists have used special tracer viruses to show that contamination of just a single doorknob can leads to the spread of viruses throughout an entire office building. The idea was to see how easily something unpleasant like norovirus spreads.
File photo of a basic door knob
File photo of a basic door knob
The new study was led by Charles Gerba of the University of Arizona, Tucson. The study used a test virus (bacteriophage MS-2) to show what might happen when more nasty viruses, such as norovirus, are present in a communal environment like an office. Nororvirus causes “winter vomiting” and it is largely spread through touch (unlike influenza, which is spread by sneezing). Norovirus infection is characterized by nausea, forceful vomiting, watery diarrhea, abdominal pain, and in some cases, loss of taste. General lethargy, weakness, muscle aches, headache, and low-grade fever may occur.
To start the research, the scientists selected a commonly touched object – a doorknob – and then tracked how quickly the virus would spread and the how many different surfaces and people ended up carrying the virus. After various periods of time (2 to 8 hours) the scientists sampled 60 to 100 fomites. Formites are surfaces capable of carrying infectious organisms (light switches, bed rails, table tops, counter tops, push buttons, coffee pots handles, sink tap handles, door knobs, phones and computer equipment), for the test virus.
The study found that within 2 to 4 hours, the test virus could be detected on 40 to 60 percent of workers and visitors in the facilities, as well as on commonly touched objects. The researchers also discovered that if disinfectant wipes or hand sanitizer towelettes were used, this reduced the transmission of the test virus by up to 90 percent. Norovirus is rapidly inactivated by either sufficient heating or by chlorine-based disinfectants, but the virus is less susceptible to alcohols and detergents.
The research, which has yet to be published, was presented at the 54th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC), an infectious disease meeting of the American Society for Microbiology.