Phylogenetic analysis suggests only one serotype of Japanese encephalitis virus.

Phylogenetic analysis was performed for different genome regions of Japanese encephalitis virus (JEV). Similar genetic groupings were identified for all analyzed genome regions including complete genomes. More extensive analysis was performed for 92 isolates (complete envelope sequences) available in the GenBank. Results of phylogenetic analysis were compared with those performed for human positive strand RNA viruses with well characterized serotypes - poliovirus (PV) and dengue virus (DEN). The observed level of the JEV inter-genotype diversity was much less than that observed across PV and DEN serotypes and was consistent with the genetic diversity observed within PV or DEN serotypes. This genetic analysis supports the contention that all known JEV isolates comprise a single serotype.