In a nutshell, they stick germ-coated fingers into their mouths, they rub their eyes, they are even known to poke a finger into a nostril. Photograph by: Photos.com , canada.com

TORONTO - Cursing your sick colleague for the infection you can feel settling into your chest? You might want to aim the finger of blame closer to home.

It's entirely possible you may have infected yourself with whatever respiratory bug has latched onto your lungs. The same can be said about the some of the stomach-wrenching gastrointestinal ailments people occasionally get.

That's because with a number of infections, people sometimes self-inoculate. They take germs they picked up on their hands when they were hanging onto bus poles or shaking a hand someone recently sneezed into and they deliver the bugs to places where those bugs can go from harmless to disease causing.

In a nutshell, they stick germ-coated fingers into their mouths, they rub their eyes, they are even known to poke a finger into a nostril.

And voila! Bug on skin becomes bug on mucus membrane — a much more porous surface and an easier route to a warm and welcoming place for the bug to migrate towards.

Handwashing and alcohol gels can slough those germs off your fingers. And that's why public health officials repeat the handwashing mantra relentlessly, particularly during cold and flu season.

But a group of researchers suggests there's a part of the prevention equation that public health folks don't stress often enough: If you kept your fingers out of your mouth-nose-eyes, you'd lower your risk of self-inoculating.

"People touch their faces, touch their mouths, pick their noses and all of that. And in those behaviours they can bring these viruses that are on their hands to the muscosa ... where they can really infect us," says Wladimir Alonso, an infectious diseases researcher at the U.S. National Institutes of Health's Fogarty International Center.

Alonso and some colleagues wrote a letter to the journal Clinical Infectious Diseases recently to make the point.

They had done a small study where they observed 249 randomly selected individuals in public spaces in Florianopolis, Brazil and on the Washington, D.C., subway system. The individuals they observed touched common surfaces and their mouth and nose area at a rate of 3.3 and 3.6 touches respectively an hour.

Their point? Handwashing alone can't keep up with the infection potential of self-inoculation events. Or as they put it, "...the opportunities for hand re-contamination in public settings occurs at a much higher rate than any viable hand washing frequency."

They suggest public health campaigns should also teach people about how they infect themselves by touching their mucus membranes, so they become more aware of the role these behaviours could play in acquiring infection.

Dr. Jody Lanard likes the suggestion. A risk communications expert based in Princeton, N.J., Lanard monitors public health messaging about influenza closely, and says officials often overstate the benefits of handwashing.

That's not to say Lanard doesn't believe in handwashing. She is in fact a big fan of the practice. But she'd prefer it if authorities stuck to the science — and says there isn't that much evidence handwashing cuts down on flu transmission. (That doesn't mean it doesn't, just that there aren't a lot of studies showing that it does. Studies aimed at answering this kind of question can be devilishly hard to do.)