Early diagnosis of Murray Valley encephalitis by reverse transcriptase-polymerase chain reaction

A 4-year-old aboriginal boy developed encephalitis due to Murray Valley enc ephalitis virus (MVE) following an earlier infection with Kunjin virus (KUN ). The illness was severe, resulting in cerebral atrophy and profound physi cal and intellectual disability. The earlier KUN infection complicated his serological profile and delayed antibody responses to MVE. By contrast, the reverse transcriptase-polymerase chain reaction (RT-PCR) assay detected MV E in serum 3 days after the onset of illness and 4 days before the appearan ce of MVE-specific IgM. We suggest that MVE-specific RT-PCR provides rapid and specific diagnosis of MVE and should be used more widely for the diagno sis of acute viral encephalitis in cases originating from flavivirus endemi c areas.