Two international research teams supported by NIGMS have developed
computer models of what might happen if the deadly avian flu, found
in birds throughout Southeast Asia, started passing efficiently
between people. Could we stop an outbreak at its source before
it spreads elsewhere? Yes, according to the simulations.
The H5N1 strain of the avian flu virus has infected a number of
species, including domestic poultry, pigs and people. Scientists
fear that a genetic exchange between bird and human flu viruses
or the accumulation of H5N1 mutations could soon make efficient
person-to-person transmission possible. With bird flu continuing
to spread in Southeast Asia, the researchers decided to model a
hypothetical human outbreak of H5N1 in this region.
Both models incorporated detailed data for Thailand on population
densities, household sizes, age distribution, distances traveled
to work and other factors. They also included information about
the flu virus, such as the possible contagiousness of an infected
person. The goals were to visualize how an outbreak might spread
and to test the effectiveness of possible intervention strategies,
such as the selective distribution of antiviral medication, vaccination
Although the models differed in the specific scenarios they simulated
and the containment measures they evaluated, the general conclusions
were similar: Preventing a pandemic would require a combination
of carefully implemented public health measures introduced soon
after the first cases appear. The need for additional measures,
the models suggest, increases as the virus becomes more contagious.
The results appear in online editions of Science and Nature.
Because computer models cannot capture all the complexities of
real communities and real outbreaks, the researchers will continue
to refine their simulations and test different scenarios as new
information becomes available.
"As these modeling approaches develop," said NIGMS director Dr.
Jeremy Berg, "they will offer policymakers and researchers powerful
tools to use in strategic planning."
Led by scientists at Imperial College in London and Emory University
in Atlanta, this new work is part of the NIGMS Models of Infectious
Disease Agent Study research network, which strives to develop
computational models of disease spread that will aid the development
of effective control strategies.