Influenza is the result of infection by a virus.
http://en.wikipedia.org/wiki/Influenza
Same is true for the common cold.
http://en.wikipedia.org/wiki/Common_cold
Viruses are not the same thing as bacteria.

To come up with a strategy which minimizes the risk of becoming infected you need to consider the complete 'life cycle' of the infectious agent, your chance of exposure and amount of exposure to the agent and the risk of your becoming infected upon exposure in all the different ways that might happen.

For all the righteous/fearless people who are under the illusion that they are 'priming' their immune system against colds and 'flu by deliberately indulging in risky behaviour, well, please don't sneeze in my direction. Because you are going to get infected.

This looks like a composite aerial flyover image (not a satellite image), a project of several aviators/participants, discussed recently on the Burning Man aviators list by Jeffrey Johnson of Pictearth.

He said the image is: "(...) our mosaic of BRC07. This was shot with a Canon G7 from Fractals 172, and [was] processed by our team. (...) Our goal was to make a time-lapse photo throughout the event to show the construction and destruction of the city, but this will have to wait for next year. (...) We do however have some great imagery above the dust storm on thursday afternoon."

A link to this image was also sent out by the Burning Man organization, on their Regional Coordinators list, incorrectly identifying it as a satellite image.