NEXT time you are bored at work, take a good look at your desk 鈥 computer, screen, piles of paper, assorted clutter, telephone and three-day-old cup of what was once, in all likelihood, coffee. A pretty barren and inhospitable place, you might think. But look closer, your office is teeming with life: from silverfish infesting forgotten files, to dust mites feasting on showers of dead skin and cockroaches cleaning up the remains of lunch. They might not keep the same hours as you but rest assured they鈥檙e there.
And their presence can have rather unpleasant consequences. 鈥淏ody fragments and faeces from insects can be highly allergenic,鈥 warns Ian Burgess, the director of Insect Research and Development, a scientific consultancy based in Royston, UK, that specialises in insect-human relationships. 鈥淲e鈥檝e come across lots of people who suffer skin reactions caused by insect fragments,鈥 he says. The static charge created by computer monitors can cause thousands of microscopic allergens to flow through the air, he adds. 鈥淭he more of your life you spend in front of the screen, the worse the situation will be.鈥
So where do the chief culprits live? Let鈥檚 begin beneath our feet. The larvae of the carpet beetle, Anthrenus flavipes, aka 鈥渨oolly bears鈥, are around 3.5 millimetres long and covered in hundreds of tiny segmented hairs. While the beetle can ruin your rugs, the larvae can damage your health. The beetles lay their eggs in the carpet. In autumn they hatch and make their way up the walls. 鈥淏ecause the hairs of these chubby little larvae are segmented, bits break off and tiny fragments get into the air,鈥 says Burgess. People who are allergic to these fragments can get very itchy skin.
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Moving up from the ground, there鈥檚 a riot of activity happening on the seat of your chair. The warm, possibly moist conditions of the average office chair make it the perfect home for dust mites. These globular, hairy arachnids are related to ticks and spiders and live in close association with humans. Around half a millimetre across, they feed off dead skin infested with fungi, and although they don鈥檛 bite or harm us directly, their faeces contain powerful allergens that happily make their way into our lungs. Dust mites are widely accepted as one of the most powerful triggers of asthma.
One study carried out at the UK鈥檚 Building Research Establishment in Watford in 1993, and led by Gary Raw, a specialist on indoor air quality, found that office chairs are commonly infested with dust mites. The study suggested that when you sit down, a plume of dust mite faeces belches out from the sides of your chair.
And what about the surface of your desk itself? Though you might dust and wipe it down on a regular basis, it doesn鈥檛 take much for nasty infestations to set in. Dave McLenachan, the Technical Manager for Rentokil IT Hygiene, based in Manchester, has a cautionary tale for anyone who thinks their desk is a temple to cleanliness. 鈥淲e visited quite a smart office the other day where this person had maggots crawling out of their keyboard,鈥 he says. Flies had laid their eggs in the warm moist cracks between the keys. They took little longer than a weekend to hatch.
Still convinced your hygiene standards are up to scratch? Try this: turn your keyboard upside down and give it a good shake. Isn鈥檛 that an exciting collection of stuff? Dead skin, hair, crumbs, sugar, possibly worse. All perfect food for flies, maggots, mites, silverfish.
Equally worrying are the disease carriers. Cockroaches are not only highly allergenic 鈥 their dung and dead scales in particular 鈥 but they come complete with a hoard of pathogens from drains, faeces and carrion.
Worried? There is worse to come. According to McLenachan it鈥檚 the unseen hazards that are the real clincher: fungi and bacteria. The smaller it gets, he says, the greater the danger.
鈥淭here are 400 times more bacteria on a desktop than on a toilet seat,鈥 says Charles Gerba, professor of microbiology at the University of Arizona in Tucson. 鈥淥ffices are worse than public toilets.鈥 And he should know 鈥 he鈥檚 been studying pathogens in public restrooms since the mid-1970s. More recently, he鈥檚 been investigating the microbes that live in the workplace. 鈥淵ou won鈥檛 believe some of the desks I鈥檝e seen,鈥 he says. 鈥淲e鈥檙e spending more time in the office than ever before and running a germ gauntlet every day at work.鈥
Contamination hotspots
Gerba鈥檚 latest research identifies the most contaminated places in the office. His team took swabs from similar office work surfaces in five different US cities: Atlanta in the humid south, Chicago in the colder north, New York on the east coast, San Francisco on the west and the dry south-west city of Tucson, Arizona. Samples were taken from offices, cubicles and conference rooms, and despite the geographic spread, the results were almost identical. The highest bacterial counts were on telephone handsets. McLenachan can back this finding with his own experience. 鈥淲e recently went to a small business in Manchester, and there was a guy there who had been off work for five months with an ear infection. His doctor concluded he caught it from a telephone.鈥
Telephone handsets were closely followed by light switches and computer mice. In conference rooms chair armrests came top of the list, although the projector remote control was also heavily contaminated with bacteria.
This in itself is nothing much to worry about. After all, we are all covered in bacteria. But some bugs are worse for you than others. Unless you clean your desk, 鈥測ou can transmit bacteria and the flu and cold virus around the office,鈥 Gerba warns, 鈥渁nd can very easily end up with more sick employees.鈥 It鈥檚 not for nothing that he uses an alcohol spray and disinfectant wipes on his own desk.
No dirty desk would be complete without the half-full coffee cup, an ideal breeding ground for furry fungi and bacteria. 鈥淐offee is a perfect biological substrate,鈥 says Gerba, who uses disposable cups in his office. 鈥淥ur study found that in a used coffee cup there are anywhere between 5000 and 300,000 bacterial cells.鈥 Gerba concentrated his research on the cups found in communal office kitchens, most of which, he says, hadn鈥檛 been cleaned properly and had crusty brown stains.
The results were disturbing, to say the least. He found that 41 per cent of the cups contained evidence of faecal contamination, with up to one in five harbouring Escherichia coli bacteria, a potential source of food poisoning. He reckons these are likely to have been spread by 鈥渃leaning鈥 with dirty dishcloths. 鈥淔unnily enough, the higher up the administrative chain [the owner was] the more bacteria there were in the cups.鈥 This he can鈥檛 explain.
And it鈥檚 not just bacteria we should be afraid of. 鈥淚鈥檝e seen some coffee cups that get furry enough to produce airborne spores 鈥 that is a problem for people with allergic asthma,鈥 says Peter Thorne, professor of toxicology at the University of Iowa College of Public Health.
The odours from mould growth, apart from being unpleasant, can also cause problems for asthma sufferers. And Thorne has a word of warning for anyone who thinks that keeping a plant by their desk improves their working environment. 鈥淧lants, particularly those in wicker baskets, get wet and mouldy and you get spores released.鈥 Not to mention pollen. The carpet around the water cooler can also prove a fertile breeding ground for fungi and bacteria.
Airborne toxins
Thorne鈥檚 latest study concerned house dust, which is far from the inert substance you might imagine. His team found bacterial endotoxins present in all 2500 samples of household dust collected from beds, sofas and floors in 831 homes across the US. Endotoxins are released into the air when the cell walls of bacteria rupture or disintegrate. Once inhaled, these endotoxins can cause inflammation of the airways. Thorne鈥檚 research has shown a direct link between the amounts of dust and the prevalence of asthma symptoms. He doesn鈥檛 expect the office to be any different.
But if you think all this means you should stay at home or in the very least sterilise everything you touch at work, take a leaf out of Anthony Hilton鈥檚 book. A microbiologist at Aston University in Birmingham, UK, Hilton has little time for alcohol sprays or disinfectant wipes around his office, and he certainly doesn鈥檛 agree with Gerba when it comes to using disposable coffee cups to protect against bacterial infection. 鈥淭he human mouth is full of micro-organisms,鈥 he says handing me a mug of coffee. 鈥淧eople kiss each other and don鈥檛 drop down dead. We鈥檝e evolved through millions of years to coexist with microbes 鈥 why should we feel the need to kill all of them when many don鈥檛 do us any harm?鈥
Hilton has a point. If this really is a problem, why don鈥檛 office workers constantly fall sick with bacterial infections and asthma attacks? He recently oversaw a study investigating the bacteria that live on computer keyboards. It looked for evidence of Enterobacteriaceae 鈥 the family of organisms commonly found in the gut. If they were present that would indicate faecal contamination. The keyboards in question were located in one of the university鈥檚 busy computer labs. Each terminal is used by at least 20 different students every day.
The researchers took swabs from the 鈥淎鈥 and 鈥淶鈥 keys of 120 keyboards. Not surprisingly, they found evidence of more bacteria 鈥 around 150 cells 鈥 on the frequently pressed 鈥淎鈥 key and only around 30 cells on the less frequently used 鈥淶鈥. Most of these were likely to be from skin 鈥 Staphylococcus aureus and S. epidermidis, which can cause skin rash. Only 3 per cent of 鈥淎鈥 keys sampled showed Enterobacteriaceae contamination. Pretty good odds, it would seem, if you like to suck your thumb at work.
So what steps should we be taking before we brave our workplace? For Hilton, it鈥檚 all a question of reasonable precautions: don鈥檛 assume everyone else is as hygienic as you, particularly if you are sharing facilities. 鈥淵ou need to implement a hygiene strategy into your own life, assuming everyone else is grubby,鈥 he advises. 鈥淣o matter what you鈥檝e been doing, wash your hands before you eat.鈥
鈥41 per cent of cups in communal office kitchens contain evidence of faecal contamination鈥
鈥淒on鈥檛 eat at your desk,鈥 says Thorne. 鈥淎s well as promoting bacteria there鈥檚 also the chance of attracting vermin such as cockroaches, ants, mice and rats.鈥 He says businesses shouldn鈥檛 skimp on cleaners and suggests we could all cut down on clutter. 鈥淚t鈥檚 easier to clean up if you can get to the dust.鈥 But he admits it鈥檚 easier said than done. 鈥淟ooking around my office I can鈥檛 say I鈥檝e really followed that advice.鈥 Even Gerba admits that by Friday his desk is a 鈥渄isaster鈥.
In most cases then, the wildlife that lives on and around your desk is nothing much to worry about. Just beware of the things you share with co-workers, such as a keyboard, coffee cup or telephone. Thorne says it鈥檚 also probably best to approach colleagues with pets or young children (who play in the dirt more frequently) with caution. They are more likely to collect endotoxins and allergens on their clothes at home, not to mention nits, and then bring them into the office.
Gerba is now trying to work out which type of office is the most contaminated. His initial findings suggest the worst desks are found in the media. For asthmatic journalists who work at home this is all very bad news indeed.
