Spread of Dollar Bills 'Helps Predict Flu Path'

Researchers at Northwestern University and the University of Indiana are using supercomputers to analyze the distribution channels of millions of US$1 bills, using the data to predict the spread of H1N1 influenza A, the New York Times reported on Monday.

The distribution channels of $1 bills are estimated to be generally identical to the paths involved in the spread of viruses because both are spread through face-to-face contact between people, but it had been impossible to accurately track the flow of $1 bills until now since they rarely leave a transaction trail.

But a website created in 1998 called "Where's George?" allows specific dollar bills to be tracked through the serial numbers of $1 notes and the ZIP codes of their holders input into the site for fun. "George" refers to George Washington, whose picture is on the $1 bill. The website presently contains data showing the distribution of 100 million $1 notes.

Prof. Dirk Brockmann of Northwestern University created a computer simulation model predicting the spread of influenza by combining this data with information on the air and land traffic networks and the flow of passengers. Last month, the simulated model predicted between 150 to 170 new cases of H1N1 Influenza A infections in the U.S. by this past Sunday. This is somewhat different than the cases of infection (226 people) the U.S. Centers for Disease Control and Prevention confirmed but not too far off.

Brockmann predicted that between 2,000 to 2,500 people would be infected in the U.S. by the end of this month. By region, Brockmann forecast the infections would be focused in areas with a high volume of mobile residents, such as New York, California, Texas and Florida.