Modeling the Geographical Spread of Influenza A(H1N1): The Case of Mexico
ABSTRACT. In this paper we examine
the mechanisms by which a given viral disease spreads successfully in a
geographical region. We propose that the key factors that cause
pandemics are of social nature, whose influence can be modeled by
mobility parameters that take into account the different ways in which
the disease can be transmitted. We use a new SEIR(S) model that is able
to reproduce the temporal behavior of a given disease within a local
homogeneous community. The geographical spread of the disease is studied
by defining a two dimensional grid of cells, weighted by the population
density, and a SEIR(S) model in each cell. The cells are coupled with
their nearest neighbors, simulating terrestrial communications, and with
long range links representing airline routes. We propose that the
mechanisms of transmission depend on the length scale. We simulate other
transportation events as thermal noise, which turns out to be a key
factor. Numerical simulations are presented to illustrate the results of
the model. Actual data on the population, communication networks and
incidence of influenza pandemic in Mexico in 2009 are used to validate
the model. The agreement with actual data is satisfactory. Furthermore,
it accounts for the effect of social distancing measures implemented in
Mexico during the 2144 Rafael A. Barrio et al. early stages of the
pandemic. Since the model can predict the development of viral epidemics
with few data from the early stages, it can be used to predict the
effect of actions to be taken to reduce and mitigate the risks of
pandemics.
I. Influenza
incidence actual data.
II.
Influenza incidence model simulation with intervention.
III.
Influenza incidence model simulation NO intervention.
