Did the movie Contagion freak you out? Me too. In fact, I was initially barred from seeing the movie because my friends weren't sure I could handle it. You see, I have what logical people will recognize as a perfectly normal and healthy awareness of the cascading festival of germs on various surfaces. My friends view this as a hilarious eccentricity.
What my filthy, disgusting friends don't seem to understand is that starting a global pandemic is as easy as one exceptionally diseased person sneezing on your hand, then you picking out an eye booger with that hand just before boarding a 747 to Tokyo. It's science, people.
That said, I am also a world traveler. I know that traveling is akin to taking a bacteria bath with a urine rinse all day long and there is nothing that can be done about it. So, when I leave on a trip, I go into my head and I say 'Head, you are going to be exposed to 244 squillion germs in the next few weeks and it's totally out of your control. So, let's flip the germ awareness switch off in the meantime and make everyone's life easier, OK?'
Because this is a topic I know well, I have been tasked with providing a list of the grossest things you will touch while traveling. And since I'm logical (hence, correct), I will follow that information up with comforting reality checks.
1. Airplane bathrooms
You thought I was going to say hostel bathrooms, right? While those backpacker microbe incubators are undeniably filthtastic, the top spot goes to airplane bathrooms. Within minutes of takeoff, airplane bathrooms are germ farms. The toilet bowl and sink are in frighteningly close proximity, and band together to form a bacterial critical mass. Furthermore, those tiny sinks make excessive splashing inevitable, and where there's moisture there are flourishing germs just waiting to give you salmonella and at least one of those hepatitises.
Reality check: The next time you're balancing precariously in an airplane lavatory during turbulence, battling to not face-plant into the toilet, calm your nerves by remembering that more people probably get killed by falling coconuts (about 150 deaths per year) than by infections contracted in airplane bathrooms (no direct reports).
2. Public transport
Some public transport systems (e.g. Singapore), are astonishingly clean. Most are not. This deluge of germs is due to the simple fact that thousands of humans rub their nasty selves on public transport surfaces every day. Places touched by hands are the filthiest, but in some cases the seats can be a veritable safari of fecal matter. If you think you'll avoid all this by renting a car during your trip, bad news. The bacteria coating gas pump handles, stick shift knobs and parking meters are statistically far worse than on public transport, since these surfaces rarely if ever get washed.
Reality check: You could probably lick 10 seats in the New York City subway and still be in less danger than riding in a car in the U.S. - over 2500 people die monthly in car accidents (no data on New York City subway seat-lickers).
3. Computer keyboards
When you use that computer in the café, hostel or hotel business center, know that you might as well be typing inside a truck stop toilet bowl. Items on the average shared desk can have up to 400 times more bacteria than a recently flushed toilet, the keyboard and telephone being the worst. The reason for this is that keyboards rarely get washed, and when they do they usually don't get washed well. Now consider that the flu virus can survive for two or three days on computer keyboards, germs live on our hands for two to 24 hours and we touch our hands to our faces -- the germ super highway to our guts -- once every three minutes.
Reality check:While you can get your fair share of illnesses from keyboards, you probably won't die. Compare this to playing video games: since the first death in 1981, when a 18-year-old man died of a heart attack after getting a high score on the arcade game Berzerk, the video game-related mortality rate has been slowly but steadily increasing.
The legend that 90% of U.S. money contains traces of cocaine is true. They also frequently have staphylococcus bacteria and fecal matter. A test by the Health Commissioner of New York found 135,000 bacteria on one especially nasty bill. Cash machine buttons are also covered in troubling quantities of germs.
Reality check: Bills are dry, which is not a great environment for bacteria to multiply. So, while bills are popularly cited as being filthy, they're not as bad as legend has it, unless you fondle a damp wad of cash immediately before a traditional Indian meal, consumed using your bare hands. Then you're screwed.
5. Other people
How do you think all those filthy surfaces became filthy in the first place? From a whole bunch of disgusting people touching them, that's how. A recent study done at Grand Central and Penn stations in New York City revealed that only 49 percent of people washed their hands after using the bathroom. Seriously, people are the worst.
Reality check: I got nothing. This factoid is endlessly horrifying to me and part of the reason why I love working from home.
You're probably expecting me to close by saying how antibacterial products changed my life and I carry them with me at all times, in a quick-draw holster of my own design, poised to douse myself and everything around me in antibacterial gel whenever needed. Not remotely true. Evidence suggests triclosan, an ingredient used in many antibacterial products, may actually make germs more resistant over time. And if there's one thing I dislike more than germs, it's super mega-germs that kill everything but the cockroaches in only a few months.
So, unless I'm sharing space with a violently ill person, I stick to normal soap and sensible hygiene, meaning washing my hands regularly, particularly after going to the bathroom and before preparing and eating food.
Leif Pettersen is a Lonely Planet author, freelance travel writer and polyglot. He's visited 48 countries (so far) and can be found on Twitter @leifpettersen.