www.wheresgeorge.com bill-tracking site

LOS ANGELES (AP) - By following the money, scientists are hoping they might better predict how diseases like a flu pandemic could spread.
Using the popular Where's George? website that tracks U.S. dollars, researchers developed a mathematical tool that could help chart the path of an infectious disease.

"We are optimistic that this will drastically improve predictions about the geographical spread of epidemics," said Theo Geisel of the Max Planck Institute in Germany, which developed the tool along with the University of California, Santa Barbara.

Details appear in Thursday's issue of the journal Nature.

Fears of a flu pandemic have arisen from the spread of bird flu, a virus that has killed more than 70 people in Asia and Europe since 2003, but which is so far spreading easily only among poultry. International health officials fear the virus could mutate into a form easily transmitted between humans.

So far, the bird flu virus is not easy to catch. But experts have warned that if it ultimately begins spreading among people, travellers are the most likely way it will become a worldwide threat.

Tracking travellers is difficult, so researchers came up with the idea of studying them indirectly by tracing how money circulates through the economy.

In the study, scientists traced the whereabouts of nearly half a million dollar bills on www.wheresgeorge.com bill-tracking site.

Users register their money and then spend it. They can monitor the money's movement online as it changes hands.

Researchers found that most of the money (57 per cent) travelled between 50 kilometres and 800 kilometres over about nine months in the United States. About a quarter of the bills moved more than 800 kilometres.

By analyzing the movement of money - and human travel - over different distances, the scientists found that the money followed a predictable pattern. The method could be used to create more realistic disease models that track the spread of germs and perhaps prevent outbreaks, they say.

The study is the most detailed to date showing the variability of travellers, said Neil Ferguson, a professor of mathematical biology at Imperial College in London.

"From the perspective of disease modelling, one thing we would like to understand better is the variability between people in their travelling," said Ferguson, who had no role in the research.

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http://www.mytelus.com/news/article.do?pageID=cp_health_home&articleID=2151717

In the past, flu pandemics spread relatively slowly because they either occurred in the age of steam or horse-power, or at a time when air travel and car ownership were restricted mainly to the wealthy.

In the 14th century, for instance, the plague known as the Black Death moved forward only a few kilometers (miles) a day, giving communities time to evacuate or make preparations, however rudimentary, for its arrival.

But the situation today is very different.

Cross-border jet travel and fast roads could spread a flu virus around the world in very short time -- perhaps in just a few days if the outbreak occurred undetected at a major transport hub.

So the big challenge is figuring out how, when and where people move.

Knowing this will greatly help efforts to identify, treat and isolate people potentially exposed to the pathogen. It would also reduce the risk of panic -- the biggest cause of economic damage in a pandemic -- and save medical resources.

Enter George Washington. Or, more precisely, the face of George Washington that appears on US currency.

A novelty Internet site called Where's George (http://www.wheresgeorge.com/) has an army of followers in the United States who, for fun, record the number of a dollar bill that they pick up in their transactions.

When someone else enters the same number, the bill's movement around the country can thus be traced -- and its fortunes can sometimes be poignant, for the banknote can pop up in some unusual places.

A trio of German physicists hit on the idea of using Where's George data as an means of getting an idea about how people travel.

They found that the banknotes mainly dispersed in a series of random steps over small distances, with occasional long hops, and there were long waiting times between displacements.

In a case study of banknotes first entered by spotters in Seattle, New York and Jacksonville in Florida, the vast majority of notes (52-71 percent) had moved less than 10 kilometers (six miles) a fortnight later.

Only a small number, between 2.9 and 7.8 percent, had moved beyond 800 kilometers (500 miles).

For a longer perspective, less than a quarter of banknotes first entered in Omaha, Nebraska travelled more than 800 kilometers in the first 100 days of their registration on the website.

More than half travelled an intermediate distance of 50-800 kilometers. And 20 percent remained within a radius of 50 kilometers of Omaha even a year later.

The findings knock down the standard model of epidemiology which suggests that viruses disperse in a wavelike manner, moving in phases over geographical areas in a way similar to the spread of fine dust particles on the surface of the water.

This model served quite well to explain past pandemics but falls short today, when travel is faster and the means of transport are many, giving more options to people in when and where they want to move, say the authors.

"The consequences of these results is that new theoretical concepts must be developed to understand the geographic spread of modern diseases," says one of the three authors, Dirk Brockmann of the Max Planck Institute for Dynamics and Self-Organisation.

What emerges to replace the one-size-fits-all model is the belief that human movement -- despite all its apparent randomness -- can be mathematically predictable if important local parameters are factored in.

"We are optimistic that this will drastically improve predictions about the geographical spread of epidemics," said another author, Theo Geisel.

The study appears on Thursday in Nature, the British weekly science journal.

Launched in 1998, making it a veteran of the Internet age, Where's George site has 3.3 million registered users, who have entered the numbers of bills, notable for a rubber stamp mark on them, worth more than 86 million dollars.

© 2006 AFP

http://www.physorg.com/printnews.php?newsid=10226

in my work I see this a great deal

I managed a fast food restuarant and oftne see bills marked with the www.wheresgeorge.com stamp. Talk about a place where bills change and move around you should see the cash flow in a fast food place. Mine is especially mobile given that it is located in a truck stop so the bills do a great deal of traveling at times...

Little do they know... I think TB2K did it!

Where's George? is currently experiencing very heavy user load.

This is most likely due to the upcoming article in "Nature" Magazine on how the
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