Expert: John Locke - 1/4/2008

Question
Hello, I was just diagnosed with pink eye and have spent the entire day doing 10 loads of laundry with bleach to make sure the entire family doesn't get it. I am concerned with the virus on everything from the frig door handle to the remotes,computer keyboard and mouse.
I sprayed disenfectant on everything but want to know if I missed some area I didnt think was effected, how long does this bacteria suvive on surfaces? In other words, can I feel safe assuming it is all dead after a week or two or does this stuff stick around for 6 months on various surfaces and we will pass it around for the next months to come, making our lives a living hell? Thansk for the help.

Answer
Thanks for using AllExperts.

Bacteria can survive very well or very poorly on particular surfaces, depending on the material, the temperature, exposure to sunlight, and a number of other factors. If indeed there were contaminated surfaces that you missed with the disinfectant, that does not mean that others will pick up those bacteria, necessarily. Let me give you some specifics; these could help you focus on materials that are  most likely to become contaminated and remain contaminated for longer periods of time.

The Journal of Food Protection found in a 2007 study that Formica and stainless steel became contaminated and transfered bacteria most easily, much more so than wooden or polypropylene surfaces. This suggests that Formica and steel surfaces in your home are the most likely sources of bacterial transfer. A 2003 study by the same journal gives some idea of the time required for bacteria to die off on a surface: the mean time to cause a significant reduction in bacterial populations varied from about 30 min to 400 min, depending on the surface. Now doesn't seem so bad: within a day, almost certainly, any residual bacteria would have died off. However, commonly used surfaces in your home (doorknobs, faucet handles, hand railings, computer keyboards, etc.) are rarely left untouched long enough for most of the bacteria on them to die. Lesser-used surfaces--which are presumably the kind you  would have missed with disinfectant spray--would be free of bacterial contamination within a week, and probably within two days.

Conjunctivitis can also be caused by viruses, however, and viruses can be more persistent. A 2006 study by the International Journal of Food Microbiology found that particular viruses could be recovered for up to a week on stainless steel, Formica, and ceramic surfaces. Assuming that contaminated surfaces received neither disinfectant nor exposure to sunlight, most surfaces would probably be free of viral contamination within two weeks. The ultraviolet rays from sunlight cause the genetic material of viruses to fall apart; if it practical where you live at this time of the year, I recommend opening your windows to catch all the sunlight you can. Glass screens out ultraviolet rays, unfortunately, so sunlight filtered through glass windows doesn't work as a disinfectant. Some disinfectants make claims against viruses and bacteria, so far as I know, while others focus only on the reduction of bacteria. Be forewarned in choosing your disinfectant product.

There's the additional element of how often we touch our faces while also touching items in the environment. The most serious risk for cross-infection probably comes not from bacteria or viruses persisting on surfaces for long periods, but from you unconsciously touching your eye and then touching another (commonly used) surface, which is then touched by someone else before you clean it. Not touching your eyes requires a surprisingly high vigilance; that may be the most important thing you can do at this time.