WASHINGTON, May 3: Worried about colds, flu and other germs? Go ahead and touch those doorknobs and elevator buttons, but watch out for the telephone, fresh laundry and sinks, a top expert advises.
And while you should always wash your hands before making a meal, many people do not realize that they should do so afterwards also, says Charles Gerba, a microbiologist and clean water expert at the University of Arizona.
''Most of the common infections -- colds, flu, diarrhoea -- you get environmentally transmitted either in the air or on surfaces you touch. I think people underrate surfaces,'' Gerba said in a telephone interview.
And when they are cautious, they are usually cautious about the wrong things. Germs do not stick where people believe they will.
''Doorknobs are usually on the low side,'' said Gerba, who has conducted dozens of surveys of bacteria and viruses in workplaces and homes. ''I guess they are not moist. Never fear a doorknob.'' A recent informal survey of a Reuters office helped him illustrate how microbes take advantage of misconceptions to propagate themselves.
Two computer keyboards, for example, carried far more bacteria than an elevator button, the handles and button on the communal microwave oven or the office water fountain, an analysis by Gerba's lab found.
Keyboards and telephones -- especially when they are shared -- are among the most germ-laden places in a home or office, Gerba said.
LUNCH COUNTER FOR GERMS
''Keyboards are a lunch counter for germs,'' Gerba said. ''We turn them over in a lot of studies and we are amazed at what comes out of a keyboard.'' In fact, the average desk harbours 400 times more bacteria than the average toilet seat, says Gerba, whose latest survey focuses on the most germ-prone professions.
''Nobody cleans the desktop, usually, until they stick to it,'' he says.
Perhaps not surprisingly, teachers have the highest exposure to bacteria and viruses, Gerba has found. Accountants, bankers and doctors also tend to have microbe-laden offices, while lawyers came out surprisingly clean in the germ-count stakes.
Offices are, however, becoming cleaner, Gerba says.
His lab does a simple overall bacteria count for its most general surveys. The person swabs each surface and sends it to Gerba's lab, which then cultures the bacteria in a lab dish.
The growth of whatever bacteria are present can be used to estimate an overall load of germs, including harmless E. coli bacteria -- which are found in the gut and are an indicator of what scientists delicately call ''faecal contamination''.
If it begins to spread, basic hygiene would be essential to avoid infection. But viruses are of course invisible to the human eye and Gerba notes that people tend not to know where the most infectious places are.
For example, the bathroom.
''Toilets get a bad rap. So does the door on the way out,'' Gerba said.
Bathroom sinks, however, are another matter. ''Sinks are usually high (in bacterial counts) to begin with,'' Gerba said. ''They have got everything a bacteria likes. It's wet, it's moist. In a home we usually find more E. coli in a sink than a toilet.'' Men's rooms, too. ''Usually the dirtiest handles in public restrooms are urinal flush handles,'' he said.
DIARRHOEA, NOT GONORRHOEA
But urban legends about getting sexually transmitted diseases in a public restroom are untrue, Gerba said. ''It's really diarrhoea, not gonorrhoea, you have to worry about,'' he said. Commonly found restroom germs include noroviruses, shigella, hepatitis A and Salmonella.
Food preparation is another good way to get germy, especially when handling raw meat, Gerba said.
And few people know just how dirty laundry is -- clean laundry.
''Most people don't realize that they actually should wash their hands after they make dinner and also after they do the laundry,'' Gerba said.
Americans have moved to short-cycle, cold-water washes to save energy and wear and tear on clothing, but this leaves viruses and bacteria largely intact.
''Water at 140 degrees F (60 degrees C) will sanitize laundry,'' Gerba said. But only 5 percent of Americans use hot water for laundry.
And viruses such as hepatitis A, rotavirus and bacteria such as Salmonella -- all of which cause stomach upsets and diarrhoea -- can easily survive the average 28-minute drying cycle.
These are all carried in faeces. ''There is about a 10th of a gram of faeces in the average pair of underwear,'' Gerba says. ''You don't want to be doing your handkerchiefs with your underwear.'' Gerba's studies are often funded by companies that make disinfectants, but Gerba says antimicrobial wipes and alcohol-based gel hand sanitizers do work.
''It has been shown that you can reduce a lot of absenteeism by using hand sanitizers,'' he says.
''We don't want to make people overly paranoid here,'' Gerba added. ''You can reduce your risk of getting colds and flu by a few simple actions. You are always gambling with germs. You just want to keep the odds in your favour.''