Co-circulation of dengue virus type 3 genotypes in Vientiane capital, Lao PDR.

During the 2012 epidemic of dengue in Vientiane capital, Lao PDR, a major serotype switch from dengue 1 to 3 was observed. A molecular epidemiology study demonstrated that dengue 3 remained the predominant serotype in 2013, but also revealed the co-circulation of two genotypes, supporting the hypothesis of multiple geographic origins of dengue 3 strains circulating in Vientiane capital

Phylogenetic relationships of DENV-3 based on the complete E nucleotide sequences (1479 nt) of 41 isolates, including 16 Lao isolates.

<p>Blue triangles and blue circles represent Lao DENV-3 genotype II and III strains respectively. Sequence alignments were performed using BioNumerics version 6.6. A maximum-Likelihood tree was constructed using MEGA version 6, based on Tamura-Nei model. Bootstrap resampling values are indicated at major nodes. Scale bar indicates number of base substitutions per site.</p

Surveillance performed by Institut Pasteur du Laos from March 2012 to December 2013.

<p>(A) Distribution of confirmed cases (i.e. RT-PCR and/or NS1 and/or culture positive) in Vientiane city (B). Dengue serotypes distribution in 2012 and 2013. Recording of dengue serotypes distribution on a four monthly basis. As the surveillance only started in late March 2012, partial data collected in April were not included in the figure.</p

List of studied Lao DENV-3 isolates.

<p>List of studied Lao DENV-3 isolates.</p