Influenza B virus encephalitis

Acute encephalitis and postinfectious encephalopathy have been reported inf requently in association with influenza A and B virus infections, We report herein a case of a 6-year-old girl with acute influenza B virus encephalit is resulting in neurological sequelae. The diagnosis was made by isolation of influenza B virus from the nasopharynx seroconversion to influenza B, an d reverse transcription polymerase chain reaction (RT-PCR) identification o f the virus from the patient's cerebrospinal fluid. Direct sequencing of vi ral RNA from the patient's nasopharynx and cerebrospinal fluid revealed ide ntical nucleotide sequences in the HA1 region of the hemagglutinin gene. Th is is the first report of influenza B virus encephalitis diagnosed by use o f RT-PCR and illustrates the need for increased awareness of influenza viru s as a cause of acute encephalitis. PCR may be a useful tool for diagnosing future cases.