RAPID DIAGNOSIS OF DENGUE VIREMIA BY REVERSE TRANSCRIPTASE-POLYMERASECHAIN-REACTION USING 3'-NONCODING REGION UNIVERSAL PRIMERS

A reverse transcriptase-polymerase chain reaction (RT-PCR) method was developed as a rapid diagnostic test of dengue viremia. To detect deng ue viruses in serum or plasma specimens, a pair of universal primers w as designed for use in the RT-PCR. Using these primers, the 3'-noncodi ng region of dengue virus types 1, 2, 3, and 4 could be amplified, but not those of other flaviviruses, such as West Nile virus, Japanese en cephalitis virus, and yellow fever virus, or the alphavirus Sindbis vi rus. The sensitivity of the RT-PCR assay was similar to that of a quan titative fluorescent focus assay of dengue viruses in cell culture. Co mbining a silica method for RNA isolation at RT-PCR dengue virus could be detected in a 6-hr assay. In a preliminary study using this method , we detected dengue virus in 38 of 39 plasma specimens from which den gue virus had been isolated by mosquito inoculation. We then applied t his method for detecting dengue viremia to 117 plasma samples from 62 children with acute febrile illnesses in a dengue-endemic area. We det ected dengue viremia in 19 of 20 samples obtained on the day of presen tation, which had been confirmed as acute dengue infection by mosquito inoculation and antibody responses. The overall sensitivity of this m ethod was 91.4% (32 of 35; 95% confidence interval [CI] = 82.2-100%). The results from testing plasma samples from febrile nondengue patient s showed a specificity of 95.4% (42 of 44; 95% CI = 89.3-100%).