Can human movements explain heterogeneous propagation of dengue fever in Cambodia?

• Published in: PLoS Neglected tropical diseases Vol. 6; no. 12
• Main Authors: Teurlai M, Huy R, Cazelles B, Duboz R, Baehr C, Vong S
• Format: Journal Article
• Language: English
• Published: 2012
• Subjects: CAMBODGE; FLAVIVIRUS; GENRE HUMAIN; MIGRATION; TRANSMISSION DES MALADIES; VIRUS DE LA DENGUE

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. (Résumé d'auteur)