RESUMO
A set of sense and anti-sense oligomeric DNA primers, degenerate in the third "wobble" base position of codons so as to match all known dengue virus sequences, was evaluated as universal primers in a polymerase chain reaction (PCR) assay for the rapid diagnosis of dengue virus infections. Virus-specific complementary DNA (cDNA) was prepared by reverse transcription (RT) of total RNA extracted from serum. Amplified cDNA was identified by nucleic acid hybridization with four serotype-specific, oligomeric DNA probes. Using sera from patients admitted with dengue fever, RT/PCR followed by nucleic acid hybridization using radiolabeled probes was 68% sensitive (50/74; 95% confidence interval [CI] = 57-78%) and 100% specific. Chemiluminescent detection of hybridized products was 62% sensitive (26/42; 95% CI = 46-75%). Using specimens from which a virus isolate had been obtained, RT/PCR followed by nucleic acid hybridization with radiolabeled probes was 80% sensitive (40/50; 95% CI = 69-91%) and 100% specific. The results suggest that RT/PCR using degenerate primers is a sensitive and specific method for the detection of dengue viruses in clinical specimens.
