Thursday Complexity Post - Modeling MRSA

Thursday Posts

May 27 2010

Description:

Mathematical Models Examine People and Bacteria Interacting

Scientists are using mathematical models to learn how disease travels through society, how people respond to an infectious epidemic, and how bacteria itself can change to adapt to new conditions created when humans alter their behavior.

Researchers from the Argonne National Laboratory are beginning a five year study that will use agent based modeling to gain new understanding of how MRSA, or methicillin resistant Staphylococcus aureus, has spread in Chicago. Argonne Scientist Charles Macal and Diane Lauderdale, an assistant professor at the university of Chicago, received a grant from the Models of Infectious Disease Agent Study, funded by the National Institutes of Health, to track the travels of MRSA using agent based modeling (ABM).

Agent based modeling is far more sophisticated than traditional epidemiological models that assume every virtual person in the model acts the same way. Complexity scholar Eric Bonabeau, who also has expertise networks and modeling, notes agent based modeling can capture emergence. To learn about epidemics, ABM can use sociological data to create a model neighborhood, and then assign factors such as age, ethnicity and location to individual agents. As a result, each agent, or virtual person, can respond in an individual way to an infectious disease outbreak. A model can simulate virtual people and virtual bacteria interacting in a virtual environment.

"How people move around creates sites of contact with other people, and that changes how the bacteria migrate through a population," Macal explained in an Argonne press release. "We find spots where people gather: large employers, schools, hospitals, or the county jail for example, and we sketch patterns of movement that could spread the bacteria." The study also examines how people react to such public health measures as screenings, announcements, or hand hygiene washing, in order to learn which are most effective. It also looks at how microbes can evolve.

"One of the best things about ABM is that we can even model the bacteria itself as an agent," Macal said. "As it travels, changes to its genome can allow MRSA to modify its own structures and behaviors to adapt to new conditions created by public response."

Macal and Lauderdale will run thousands of simulations on Aergonne's computers to test impact of varying social and environmental factors. Eventually, scientists hope to a develop a framework model for disease transmission that would allow researchers from any city use their own population and disease data and get information that could help them slow transmission.