Dengue virus infections: comparison of methods for diagnosing the acute disease

The control of dengue depends solely on the control of the insect vector and efficient diagnosis of human cases as no vaccines or specific treatments are currently available. Existing diagnostic methods for suspected clinical cases are complicated by the short duration of viraemia and by serological cross-reactivity with epitopes from other flaviviruses.To evaluate PCR-based tests (nested reverse transcription (RT)-PCR and real-time RT-PCR) for the detection and serotyping of dengue virus and compare the results with those obtained with a widely used immunological test (IgM antibody capture ELISA-MAC-ELISA).The PCR-based methods were more effective in the first few days of infection, whereas the MAC-ELISA became more sensitive 5 or 6 days after disease onset. These results suggest that the best method for dengue diagnosis is a combination of PCR-based and immunological tests. Real-time RT-PCR was more sensitive than the nested RT-PCR approach. Furthermore, it was rapid, reproducible and highly specific, making it a potential method for the diagnosis of dengue fever.