Browsing by Autor "Xavier de Lamballerie"

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Clinical significance of intra-host variability of Dengue-1 virus in venous and capillary blood
(Elsevier BV, 2013) Élodie Descloux; C. La Fuentez; Yelin Roca; Xavier de Lamballerie
Molecular Epidemiological Analysis of Dengue Fever in Bolivia from 1998 to 2008
(Mary Ann Liebert, Inc., 2009) Yelin Roca; Cécile Baronti; Roberto Jimmy Revollo; Shelley Cook; Roxana Loayza; Läétitia Ninove; Roberto Fernández; Jorge Vargas Flores; Jean-Pierre Hervé; Xavier de Lamballerie
Dengue fever was first recognized in Bolivia in 1931. However, very limited information was available to date regarding the genetic characterization and epidemiology of Bolivian dengue virus strains. Here, we performed genetic characterization of the full-length envelope gene of 64 Bolivian isolates from 1998 to 2008 and investigated their origin and evolution to determine whether strains circulated simultaneously or alternatively, and whether or not multiple introductions of distinct viral variants had occurred during the period studied. We determined that, during the last decade, closely related viruses circulated during several consecutive years (5, 6, and 6 years for DENV-1, DENV-2, and DENV-3, respectively) and the co-circulation of two or even three serotypes was observed. Emergence of new variants (distinct from those identified during the previous episodes) was identified in the case of DENV-1 (2007 outbreak) and DENV-2 (2001 outbreak). In all cases, it is likely that the viruses originated from neighboring countries.
Molecular Epidemiology of Yellow Fever in Bolivia from 1999 to 2008
(Mary Ann Liebert, Inc., 2010) Cécile Baronti; Norma Janeth Velasquez Goitia; Shelley Cook; Yelin Roca; Jimmy Revollo; Jorge Vargas Flores; Xavier de Lamballerie
Yellow fever (YF) is a serious public health problem in Bolivia since at least the 19th century. Surprisingly, very limited information has been made available to date regarding the genetic characterisation and epidemiology of Bolivian YF virus (YFV) strains. Here, we conducted the genetic characterization of 12 human isolates of YFV collected in Bolivia between 1999 and 2008, by sequencing and analysis of two regions of the viral genome: a fragment encoding structural proteins "PrM" (premembrane and envelope) and a distal region "EMF," spanning the end of the virus genome. Our study reveals a high genetic diversity of YFV strains circulating in Bolivia during the last decade: we identified not only "Peruvian-like" genotype II viruses (related to previously characterized Bolivian strains), but also, for the fist time, "Brazilian-like" genotype I viruses. During the complete period of the study, only cases of "jungle" YF were detected (i.e., circulation of YFV via a sylvatic cycle) with no cluster of urban cases. However, the very significant spread of the Aedes aegypti mosquito across Bolivian cities threatens the country with the reappearance of an urban YFV transmission cycle and thus is required a sustained epidemiological surveillance.