An epidemic of encephalitis associated with human enterovirus B in Uttar Pradesh, India, 2008.

Background: Human enteroviruses (HEVs) are a rare cause of encephalitis, presenting in endemic or epidemic form.
Objectives: The aim of the study is to identify and characterise the causative agent of the encephalitis epidemic, which occurred in Uttar Pradesh, India during the summer of 2008.
Study Design: A total of 90 cerebrospinal fluid (CSF) specimens were collected between June and October 2008 from children with symptoms of encephalitis admitted to Chhatrapati Shahuji Maharaj Medical University and Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India. Conventional and molecular methods were used to identify and characterise the viral agent associated with the epidemic.
Results: Enterovirus RNA was detected in 37 (41.11%) of 90 CSF samples by real-time polymerase chain reaction (PCR). Seroneutralisation, amplification and sequencing of the 3'-end of the VP1 region of EV isolates revealed coxsackievirus B5 (CBV) and echovirus 19 (ECV) as the main serotypes causing this epidemic. Phylogenetic analysis showed that sequence divergence among the same serotypes was 0-4% at the nucleotide level.
Conclusions: This is the first report suggesting that CBV 5 and ECV 19 may be responsible for an epidemic of encephalitis in India. These serotypes were variant and evolved within the studied area.
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