Influenza surveillance mechanisms in Mexico were adequate during the fast-spreading H1N1 outbreak in 2009, yet Mexico did not have the infrastructure to quickly identify the emergence of this novel strain, according to an Arizona State University (ASU) epidemiologist.

Carlos Castillo-Chavez, director of ASU's Mathematical, Computational and Modeling Sciences Center in the College of Liberal Arts and Sciences, took a close look at factors impacting the influenza dynamics within Mexico during a presentation Feb. 21 at the annual meeting of the American Association for the Advancement of Science. Castillo-Chavez's presentation, "Life in the Fast Lane: H1N1 Pandemic Dynamics in Mexico's Central Influenza Corridor," is part of a session of how mathematics is used for investigating biological hierarchies.

"Mexico public health officials took immediate and massive social-distancing measures during the initial outbreak that were effective, but only over a short-time scale," says Castillo-Chavez. "But the second wave hit Mexico and the rate of infections exceeded those over the months of April through June 2009. The combination of large movements of people in Mexico's central influenza corridor and past strict social-distancing measures seemed to have had a dramatic effect on the ongoing influenza dynamics within Mexico. Fortunately, disease severity has not been as devastating as in past pandemics."

In his analysis of Mexico's response to the H1N1 virus and the dynamics surrounding the influenza outbreak, Castillo-Chavez addressed a number of lingering questions, including whether social-distancing measures (no longer in effect) combined with summer school breaks not only slowed down the first wave but could have resulted in a less manageable second wave.

He also broke down what was learned from Mexico's experience to answer such questions as: Is the lack of advanced diagnostic facilities and uniform surveillance systems, common in poor nations, "good" for the rest of the world? What will be the impact of the limited access that the have-nots (individuals or nations) have to adequate supplies of antiviral drugs and the H1N1 vaccine on the dynamics of H1N1? What are the optimal public health policies for non-wealthy nations?

Castillo-Chavez is a Regents' Professor and the Joaquin Bustoz Jr. Professor of Mathematical Biology in ASU's School of Human Evolution and Social Change. He is an AAAS Fellow and recipient of the 2007 AAAS Mentor Award. His research is carried out at the interface of the mathematical, natural and social sciences and puts emphasis on the role of dynamic social landscapes on disease dispersal; the role of behavior on disease evolution, the role of behavior, environmental and social structures on the dynamics of addiction, the identification of mechanisms that facilitate the spread of diseases across multiple levels of organization.

Source:
Carol Hughes
Arizona State University