Sequences of terminal non-coding regions from four dengue-2 viruses isolated from patients exhibiting different disease severities.

We have determined the 5' and 3' non-coding regions (NCR) of four dengue-2 viruses isolated from dengue patients with different clinical severities in Nakhon Phanom, Northeastern Thailand in 1993. The results were compared to prototype dengue-2 strains and were found to have highest homology with the New Guinea C strain. The sequence of the 5' NCR was completely conserved among all 4 isolates and were identical to the sequence of the New Guinea C strain. Homology of the 3' NCR sequence of the four isolates with the prototype strain ranged from 97.3 to 97.8%. Isolate ThNH-p11/93 from a mild dengue fever case showed the highest divergence from the prototype strain and the rest of the isolates from severe hemorrhagic cases, (1.11%). This includes a change in triad 297-299 nucleotides from the 3' terminus. Computer predicted secondary structures showed that isolate ThNHp-11/93 had significant structural differences from the other three isolates at this region.