10 Germ Myths Under the Microscope

Dec. 29, 2008— -- As you take steps to avoid the germs and viruses that proliferate as winter progresses, you've no doubt received a good share of advice on how to avoid catching whatever's going around.

ABCNews OnCall+ spoke with experts about some of the popular myths about germs that tend to spread as fast as the bacteria themselves this time of year.

Is a dog's mouth cleaner than a person's? How unsafe are public toilet seats? Some of these questions lack hard data, and the study findings sometimes conflict.

So before taking advice from your friends, you might want to check their wisdom about our microbe neighbors.

Dr. J. Owen Hendley, professor of pediatric infectious disease at the University of Virginia Children's Hospital, said that this myth has been a persistent one.

Of getting an infection, he said, "I guess you could, but I've never known of a documented case where that actually happened."

But that has not stopped the myth. Hendley noted that the concern might have originated with a fear that syphilis could spread through toilet seats. He said that that fear is likely behind the design of many public toilet seats in which the seat itself is open in the front, preventing contact between the person and the seat in that area.

But the knowledge that sitting directly on the seat doesn't spread the germs doesn't seem likely to make it more appealing.

Get Your Questions Answered at the ABCNews.com OnCall+ Cold & Flu Center

"I couldn't imagine it [spreading infection]," said Hendley. "Which is not to say I would like to go into a public restroom and sit down on the toilet seat."

Maybe not. A few years ago, the Discovery Channel's "Mythbusters" tackled the issue.

In its tests, the show placed toothbrushes near the toilet, in a bathroom cabinet and in the kitchen of a house.

At the end of the test, the show declared the toilet-toothbrush-shower a myth, with all three toothbrushes having similar amounts of fecal bacteria, regardless of placement.

So we know there's a spray when the toilet gets flushed, but it's unclear how far it travels and what ends up where.

Ultimately, the problem may be that there hasn't been a peer-reviewed study of toothbrush hygiene. We don't know where the bacteria travel, and we don't know the source of bacteria that may have ended up on the toothbrushes placed in various areas.

"A lot of the droplets that are generated when you flush a toilet, they are too large to spread probably more than a foot or two," said Sattar.

Fecal bacteria means the bacterium E. coli, which is found in fecal matter, among other things. While often used to gross someone out about bacterial contamination, just finding it doesn't mean the germs came from the toilet.

So it's not entirely clear that your toothbrush is showering in your toilet water just because it's nearby. But it may not be a bad idea to put the lid down when you flush.

Sattar said his team had sampled the air around driers in various public restrooms as people were using them and found no increase in bacteria.

As to the rumor that dust accumulates inside, he said his team had taken apart multiple hand driers in places like bus stations and busy shopping centers and also found nothing.

The real worry about hand driers, said Scott, is having to touch something to start them.

"It's always good to look for systems that don't require you to touch," she said, because the buttons will accumulate germs.

Ideal restrooms, Scott said, wouldn't have doors or handles for the faucet, and would have electronic eyes to start hand driers, faucets and flush mechansms on toilets.

"No-touch is ideal," Scott said.

She noted that washing with soap and water doesn't remove all the microbes from our hands, because some are an important part of our skin, and even if we did kill them, they would return.

Given that regular soap and water removes the germs, there is no need for an antibacterial agent, and it probably won't work anyway.

"The speed of action of these ingredients that are added is rather slow, so that they are not there on the hands long enough to present the desired level of reductions," said Sattar.

So the antibacterial agents added to soap, typically triclosan, isn't effective in this case but may present problems, as our next myth explains.

Scott notes that resistant strains of bacteria have been created in labs using triclosan, although it remains to be seen if it will happen in the natural environment.

"It's something that's been observed in the laboratory, and it's something that needs to be researched," she said.

For Sattar, the long-term risks of triclosan in the environment also need to be looked at.

"Their accumulation in the environment or chronic exposure to them on a long-term basis, especially for children, may have a long-term risk that we will not discover until later on," he said.

Ultimately, Sattar said, antibacterial soap doesn't do enough to justify its use. "Don't take risk without a demonstrated benefit," he said.

So in order to keep sponges from being bacteria farms for your kitchen, several steps should be taken.

Hendley said he maintains separate counter and dish sponges and makes sure to have detergent in the sponge whenever he uses it.

Scott said that maintaining separate dish and counter sponges is key.

"I think the best practice is to keep the sponge at the kitchen sink for washing up, and to use paper towels for wiping down kitchen surfaces," she said.

Sponges can be placed in the dishwasher or laundry to decontaminate them, although the research on how much that helps remains unclear.

Perhaps the best way to clean sponges is by microwaving them, but it's important to ensure that they are wet before putting them in.

Scott explains that the wear on the cutting board affects its cleanliness more than the material from which it's made.

"The most important thing is, whatever cutting board anyone's using, it's not badly scoured," she said.

So why did we deem this a fact?

As Scott explained, a plastic cutting board is easier to clean, by bleaching it at the sink or putting it through the dishwasher.

In any case, she noted, separate cutting boards should be used for raw chicken or beef and vegetables.

And ultimately, the plastic cutting boards are more sanitary, Scott said, because they're cheaper -- so people are more likely to throw them out and replace them.

There doesn't appear to much hard data on what the cosmetics at the counter contain, but their usage could lead to the spread of infection.

Scott's advice is to stick to single use samples and avoid the communal beauty sources.

"If I were forced to be bitten by a dog or a human, I'd take a dog," said Hendley.

But that doesn't mean a dog's mouth has fewer microbes, or that it's "clean."

"I'm thinking, what was the dog last licking?" said Scott.

Hendley and Scott noted that dogs tend to lick themselves, particularly after scraping themselves, and their mouths tend to come in contact with animal feces.

Scott also noted that germs can be picked up by stroking the animals, and you should wash your hands anytime you touch them.

ABCNews OnCall+ has previously looked at the issue, and travel can increase risk of flu (which comes from a virus, not a germ), but that is a concern in any crowded area, not just an airplane.

The recirculated air, however, is not as much of a concern as it may once have been.

"It probably was true in the sense that inside of an aircraft cabin, if filled to capacity, you would have a lot of people breathing germs in and out," said Sattar.

But, he said, "More recent aircraft design has created engineering controls which reduce that risk."

Sattar notes that HEPAs, or high efficiency particulate arresters, which were developed around World War II, trap tiny particles in the air so that any particle that might be carrying viruses or bacteria is caught when viruses pass through the air system in the aircraft.

So planes, like any crowded area, pose an increased disease risk, but it isn't clear how much, if any, of that is due to the recirculated air.

Sattar also noted that the World Health Organization will be examining this issue to ensure that passengers aren't sharing illnesses with their fellow travelers.

-------
Cold & Flu season is here! Visit the ABCNews.com OnCall+ Cold & Flu Center to get answers to all your questions about these nasty germs.