Determination of dengue virus serotypes in Thailand using PCR based method.

A reverse transcriptase-polymerase chain reaction (RT-PCR) and a single-tube multiplex PCR assay was modified for typing of dengue virus in different geographical areas of Thailand during 2000-2001. A set of primers (D1 and D2) was used to generate the RT-PCR product of 511 bp in size which subsequently underwent a single-tube multiplex PCR amplification using the highly specific primers for each of the dengue virus serotypes (D1, TS1, TS2, TS3 and DEN4). The PCR products of 482, 119, 290 and 392 bp in size were generated for dengue virus serotypes 1, 2, 3, and 4, respectively. Each set of specific primers showed no amplification of non-specific and non-target PCR products from human genomic DNA. The method was applied for investigation of 637 human blood samples in Thailand during 2000-2001 and found that 71, 43, 28, and 43 patients were classified as having a single infection with serotypes 1, 2, 3, and 4, respectively. Multiple infections with two or more dengue virus serotypes were also detected.