Molecular epidemiology of dengue-1 and dengue-4 viruses Chungue, Eliane and Cassar, Olivier and Drouet, Marie Thérèse and Guzman, Maria Guadalupe and Laille, Manola and Rosen, Léon and Deubel, Vincent,, 76, 1877-1884 (1995), doi = https://doi.org/10.1099/0022-1317-76-7-1877, publicationName = Microbiology Society, issn = 0022-1317, abstract= Genetic variation between geographically and temporally distinct isolates of dengue-1 (DEN-1) and dengue-4 (DEN-4) viruses was investigated. The nucleotide sequences of a fragment of the envelope protein gene encoding amino acids 28 to 87 of 35 DEN-1 isolates and 28 DEN-4 isolates were determined. Maximum nucleotide sequence variation was 6.9% and 4.9% for DEN-1 and DEN-4 viruses, respectively. Taking a divergence of 6% between the nucleotide sequences as the cut-off value, three genotype groups were defined for DEN-1 viruses, whereas only one was observed for DEN-4 viruses. Molecular analysis of isolates from the South Pacific permits the classification of the recent strains of DEN-1 (1988–1989 epidemics) into a genotype distinct from the genotype which comprises earlier strains. This observation suggests that the recent epidemics were due to the introduction of a new genotype rather than to the re-emergence of the earlier strain., language=, type=