Can Human Movements Explain Heterogeneous Propagation of Dengue Fever in Cambodia?
Abstract
Background: Determining the factors underlying the long-range spatial spread of infectious diseases is a key issue
regarding their control. Dengue is the most important arboviral disease worldwide and a major public health problem in
tropical areas. However the determinants shaping its dynamics at a national scale remain poorly understood. Here we
describe the spatial-temporal pattern of propagation of annual epidemics in Cambodia and discuss the role that human
movements play in the observed pattern.Methods and Findings: We used wavelet phase analysis to analyse time-series data of 105,598 hospitalized cases reported
between 2002 and 2008 in the 135 (/180) most populous districts in Cambodia. We reveal spatial heterogeneity in the
propagation of the annual epidemic. Each year, epidemics are highly synchronous over a large geographic area along the
busiest national road of the country whereas travelling waves emanate from a few rural areas and move slowly along the
Mekong River at a speed of ,11 km per week (95% confidence interval 3–18 km per week) towards the capital, Phnom
Penh.Conclusions: We suggest human movements – using roads as a surrogate – play a major role in the spread of dengue fever
at a national scale. These findings constitute a new starting point in the understanding of the processes driving dengue
spread.
Domains
Geophysics [physics.geo-ph]Origin | Publisher files allowed on an open archive |
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