Demonstration of concurrent dengue 1 and dengue 3 infection in six patients by the polymerase chain reaction.

A dual viremia resulting from naturally acquired dengue 1 and dengue 3 infections in six patients experiencing a dengue-like syndrome during the epidemic in New Caledonia in 1989 is reported. Serotype identification was first based on virus isolation in mosquito cells and immunofluorescence using type-specific monoclonal antibodies. The double infection was confirmed directly in blood samples by the polymerase chain reaction (PCR) on genomic RNA and hybridization of the amplified cDNA fragments with type-specific DNA probes.