Center for Infectious Disease and Vaccine Research; Department of Medicine, Division of Infectious Diseases and Immunology
Dengue is a mosquito-borne viral infection that in recent years has become a major international public health concern. Dengue hemorrhagic fever (DHF), first recognized in Southeast Asia in the 1950s, is today a leading cause of childhood death in many countries. The pathogenesis of this illness is poorly understood, mainly because there are no laboratory or animal models of disease. We have studied the genetic relationships of dengue viruses of serotype 2, one of four antigenically distinct dengue virus groups, to determine if viruses obtained from cases of less severe dengue fever (DF) have distinct evolutionary origins from those obtained from DHF cases. A very large number (73) of virus samples from patients with DF or DHF in two locations in Thailand (Bangkok and Kamphaeng Phet) were compared by sequence analysis of 240 nucleotides from the envelope/nonstructural protein 1 (E/NS1) gene junction of the viral genome. Phylogenetic trees generated with these data have been shown to reflect long-term evolutionary relationships among strains. The results suggest that 1) many different virus variants may circulate simultaneously in Thailand, thus reflecting the quasispecies nature of these RNA viruses, in spite of population immunity; 2) viruses belonging to two previously distinct genotypic groups have been isolated from both DF and DHF cases, supporting the view that they arose from a common progenitor and share the potential to cause severe disease; and 3) viruses associated with the potential to cause DHF segregate into what is now one, large genotypic group and they have evolved independently in Southeast Asia for some time.
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Copyright 1998 by The American Society of Tropical Medicine and Hygiene. Publisher PDF posted as allowed by the publisher's author rights policy at http://journals.asm.org/site/misc/ASM_Author_Statement.xhtml.
Am J Trop Med Hyg. 1998 Jan;58(1):96-101. DOI 10.4269/ajtmh.1998.58.96 Link to article on publisher's website
dengue hemorrhagic fever, dengue virus
Rico-Hesse, Rebeca; Harrison, Lisa M.; Nisalak, Ananda; Vaughn, David W.; Kalayanarooj, Siripen; Green, Sharone; Rothman, Alan L.; and Ennis, Francis A., "Molecular evolution of dengue type 2 virus in Thailand" (1998). Infectious Diseases and Immunology Publications and Presentations. 300.