JŽr™me Cukier

VAST 2011 Challenge 
Mini-Challenge 1 - Characterization of an Epidemic Spread

Authors and Affiliations:

JŽr™me Cukier, OECD

Tool(s):

I used Python to clean and prepare the dataset, and Protovis (M. Bostock, J. Herr, V. Ogievetsky, Stanford University) to develop the interactive tool that visualizes the data. 

The tool can be downloaded at http://dl.dropbox.com/u/5259106/mc1.zip

 

Video:

 http://youtu.be/i5g7_iX9tVQ?hd=1 

ANSWERS:

MC 1.1 Origin and Epidemic Spread: Identify approximately where the outbreak started on the map (ground zero location). If possible, outline the affected area. Explain how you arrived at your conclusion.

 

The disease started affecting people on a large scale on the morning of the 18th of May in the downtown area. There were sporadic reports of similar symptoms in the previous night in various areas of town, including in the Smogtown area where the infection most likely originated.

 

This shows the downtown area on the morning of the 18th. The red squares indicate that many people are tweeting reporting symptoms

Later that day, we see how the disease has spread to the rest of town.


MC 1.2 Epidemic Spread: Present a hypothesis on how the infection is being transmitted. For example, is the method of transmission person-to-person, airborne, waterborne, or something else? Identify the trends that support your hypothesis. Is the outbreak contained? Is it necessary for emergency management personnel to deploy treatment resources outside the affected area? Explain your reasoning.

I have two hypotheses for the start of the infection.

á       Most likely: the explosion of the chemical plant in Smogtown.


á       Also possible: an accident involving a chemical truck on a bridge over the VAST river, just west of the downtown area.

Both events occurred on the 17th of May. That day, the wind was blowing westward.

Since the disease struck the downtown area, to the East, this rules out an airborne-only transmission mode. Instead, the toxic chemicals flowed down the river from the spill location.

Then, the disease spread from the downtown area to the residential areas as workers returned home. This indicates a person-to-person transmission mode.

At the end of the period the disease isnÕt contained. Since it is contagious, everyone interacting with a Vastopolitan is at risk. The waterborne pollutant which caused the infection can also have travelled downstream to other towns.