I'm writing this on Saturday for posting on Monday and wondering what the news about the swine flu outbreak will be two days from now. Will it still be "just" an outbreak on Monday, or will the names "epidemic" or "pandemic" be in use by then? A very informative, helpful article about this issue was published by New Scientist this past weekend.
Complexity science is one area of study that seems to have a lot to contribute to the understanding and, perhaps, management of epidemics and pandemics. It has been known for a very long time that viral epidemics such as measles occur in ways that can be described by nonlinear dynamics and chaos theory. Some older papers on this subject can be found here and here and here.
A friend of mine, Alessandro Vespignani of Indiana University, has done a lot of research on mathematical modeling of epidemics and is a proponent of the power of complex systems modeling for understanding and even controlling pandemics.
In 2007 Alex and his colleagues took a look at historical records for the SARS outbreak and were able to show that the spread of this disease could be traced to air travel patterns. Their work, which used network theory, one of the newest tools in the complexity science toolbox, is an example of an approach that could be used by public health professionals as they work to predict and manage new disease outbreaks.
Public health professionals would be wise to take a look at the predictive capabilities of complex systems modeling. As Neal Pearce and Franco Merletti argue in an editorial in the International Journal of Epidemiology,
"...the health of a population can be viewed as a complex adaptive system. A population is not just a collection of individuals; rather, each population has its own history, culture, and socioeconomic structures, which survive despite massive global economic change while at the same time being affected and shaped by such change. The health of a population is shaped by, and shapes, the sociocultural context in which the population lives. Thus, although the occurrence of disease can be studied at many different levels, including ecosystems, populations, individuals, and molecules, it has been argued that the population level is fundamental for epidemiology."
Whether the swine flu outbreak turns into a serious epidemic or even pandemic like SARS remains to be seen. However, it seems clear to me that the science of complex systems is eminently applicable to this topic and urgently needed by public health professionals.