Sustained transmission of dengue virus type 1 in the Pacific due to repeated introductions of different Asian strains

摘要

Outbreaks of dengue due to dengue virus type 1 (DENV-1) occurred almost simultaneously in 2001 in Myanmar and at multiple sites\udalmost 10,000 km away in the Pacific. Phylogenetic analyses of the E protein genes of DENV-1 strains recovered from Asia and the Pacific\udrevealed three major viral genotypes (I, II, and III) with distinct clades within each. The majority of strains from the Pacific and Myanmar,\udand a number of other Asian strains fell into genotype I. Genotype II comprised a smaller set of Asian and Pacific strains, while genotype III\udcontained viruses from diverse geographical localities. These analyses suggested that the continuing outbreak of dengue in the Pacific has\udbeen due to multiple, direct, introductions of dengue viruses from a variety of locations in Asia followed by local transmission. There was no\udevidence that the introduction of these viruses into the Pacific was associated with any adaptive changes in the E protein of the viruses.