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Descripción
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| Viral infections may have enormous consequences for human, animal and plant welfare, therefore a having great socio-economic impact. Understanding the factors that modulate the appearance and evolution of viruses could allow us to design better prevention and control strategies for the diseases that they cause. Dengue Virus type 2 (DENV2) is a mosquito-transmitted single -stranded positive-sense RNA virus of the Flaviviridae family, which may cause on its most virulent strains hemorragic fever. This virus is endemic from Asia and America, but lately cases of hemorragic fever caused by DENV2 have been reported in Europe. It has been hypothesized that this expansion in the virus distribution may affect DENV2 evolution. However, this hypothesis has been seldom tested empirically. This study was carried out with the intention of understanding the dispersion patterns of DENV2, and their effects in virus evolution. To achieve this, first the genetic structure of different populations of DENV2 according to geographic location was studied (both at the continent and at the country level) revealing a strong genetic structure depending on geographical location. A Bayesian reconstruction of the DENV2 phylogeny into a calescent framework was performed in order to reconstruct the evolutionary history of the virus. This reconstruction indicated that DENV2 diverged around 9,000 years ago. The addition of a model of discrete diffusion allowed reconstructing the migration routes of the virus. Sequences grouped in different clusters depending on the country of origin, and these country-specific clusters grouped also according to the continent of origin. Accordingly, results indicated that the origin of the virus was in India, and that early in its evolutionary time the virus dispersed into America. After this initial dispersion, the virus evolved separately in Asia and America. Only recently, in the last 40 years, new cross-continental virus movements were detected. However, these long-distance movements have not affected the genetic structure of DENV2. Taken together, results of this work allowed us to conclude that although migration have shaped the evolutionary history of DENV2, recebnt changes in migration patterns have not altered DENV2 evolution. We hypothesize that other forces such as local selection pressures may more important in determining the genetic diversity of DENV2 populations. | |
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Internacional
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No |
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Fecha
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Lugar
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Universidad Politécnica de Madrid |
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Tipo
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Otro tipo de responsabilidad |