Diseases and Networks

We did a rapid survey of diseases and the role that networks play in the spread of diseases. We started with a brief discussion of the plagues that besieged Europe and parts of Asia and Africa in the middle ages (14th century). We then talked about John Snow and the 1854 Broad Street Cholera outbreak as an early example of modern methods applied to the study of disease spread. John Snow is now known as the “father” of epidemiology, which is the study of how diseases spread in a population. We then moved from 19th century England to 20th century US and the early history of HIV  in the US. In the early 80s, at a time when AIDS was referred to as the “gay cancer” there was a great deal of discrimination and political inaction associated with AIDS. We also talked about the first book on AIDS “And the Band Played On” by investigative reported Randy Shilts. Shilts himself died from AIDS a few years after the publication of his book. This book promoted the idea (based on a 1984 American Journal of Medicine article) that a French-Canadian Flight Attendant names Gaetan Dugas was “Patient Zero” for AIDS in the US. In other words, the claim was that Dugas had brought AIDS from Africa and then spread it to cities through the innumerable sexual partners he had. This theory has been questioned and in a 2007 article in the Proceedings of the National Academy of Science (PNAS), and it is claimed that AIDS moved from Africa to Haiti and then to the US in the 60s. After discussing AIDS, we also talked about a more recent disease-outbreak, namely the 2003 outbreak of SARS.
Our discussion then moved on to how epidemiologists (and mathematicians, statisticians, and computer scientists) model the spread of disease. I showed a game designed by Princeton University mathematician John Conway, called the Game of Life. Here are some applets that let you play the game and here is John Conway on youtube talking about the complexity that his simple game can lead to. Models for disease-spread are similar to Conway’s Game of Life, in that the disease-status of an individual in each time step depends on the disease-status of “neighboring” individuals. Here is an example of a  Disease spread simulation involving individuals that can, in each time step, be susceptible, infected, or recovered. Finally, we talked about this Disease spread strategy game.
Homework:
Describe a future (imagined) world-wide disease outbreak, providing as much detail as possible.  Include biological details such as whether the disease is viral or bacterial, how it spreads (cough/sneeze vs touch), whether it involves carriers such as rodents, etc. Also, describe a typical individual’s reaction to the infection, including whether the individual can be infectious before showing symptoms and if so for how long. Also, describe  how the disease affects the very young and the old.
Then describe where the disease starts and how it spreads across the world. Include the effects of various transportation networks such as airlines, cargo ships, etc., and also the highway system and rail networks within countries. Also, include the effects of social networks induced by colleges, schools, work places with large number of employees, etc.
In order to make your story as realistic as possible read up on the spread of HIV, SARS, etc. by following the links posted above. You might also want to watch the movie Contagion, that was released last year.
I would like your final description to be no more than 2 typed, single-spaced pages using a 11 pt font. On Tuesday, in class I would like each of you to share with the class a first draft of this description.
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