Improved molecular detection of dengue virus serotype 1 variants

Abstract

The dengue virus molecular typing method described by Lanciotti and coworkers (R. S. Lanciotti, C. H. Calisher, D. J. Gubler, G. J. Chang, and A. Vance-Vorndam, J. Clin. Microbiol. 30:545-551, 1992) is used worldwide for diagnosis and surveillance. However, it failed to detect DENV-1 variants in Cambodia due to a point mutation. We describe an improvement of the method that allows the detection of additional DENV-1 strains, including potential variants.

FIG. 1.

Alignment of nine sequences of dengue 1 viruses isolated in Cambodia, with the DENV-1 Nauru/74 strain sequence included as a reference (10). Identities at nucleotide positions are shown by dots. The sequence numbering is based on the genomic Nauru/74 strain sequence. The target region of the TS1 and TS1bis primers is shown in the gray box, and primer sense is indicated by the horizontal arrow. The vertical arrow shows nucleotide position 568 (letters in bold), where a TS1 primer mismatch occurs.

FIG. 2.

Alignment of the four sequence patterns representative of the nine sequences of dengue 1 viruses isolated in Cambodia, along with other dengue 1 virus sequences available from the GenBank/EMBL databases. Identities at nucleotide positions are shown by dots. The sequence numbering is based on the Nauru/74 sequence. The target region of the TS1 and TS1bis primers is shown in the gray box, and primer sense is indicated by the horizontal arrow. The vertical arrow shows position 568 (letters in bold), where the TS1 primer mismatch occurs. Strains are designated as follows: accession number/geographical origin, year of isolation (isolate). vcsd, vaccine candidate strain derived; ge, genetically engineered.