Rapid detection of dengue viral antigens by counterimmunoelectrophoresis.

Counterimmunoelectrophoresis (CIE) was applied to detect dengue viral antigen in an experimental system and in clinical situations. In the experimental system, all four types of dengue viruses (dengue 1 to 4) were detected when tested against rabbit hyperimmune sera. With homologous antibody, antigen could be detected when hemagglutinating titer was as low as 1:20. In clinical situations, 67% of the sera of patients with dengue hemorrhagic fever collected on day 4 after onset of fever were positive by CIE. Antigens could be detected most frequently from day 4 to day 7. In 11% of the cases, antigens were found to persist as long as 38 days. Validity of this detection was confirmed in some cases by immunologic methods. Virtues of CIE are its technical simplicity, rapidity, and economy.