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Molecular phylogenetic and evolutionary analyses of Muar strain of Japanese encephalitis virus reveal it is the

Manal A F Mohammed1, Sareen E Galbraith, Alan D Radford

  • 1Brain Infections Group, Institute of Infection and Global Health, University of Liverpool, Liverpool, UK.

Infection, Genetics and Evolution : Journal of Molecular Epidemiology and Evolutionary Genetics in Infectious Diseases
|March 1, 2011
PubMed

Insights

Japanese encephalitis virus (JEV), a major cause of epidemic encephalitis, has a newly identified fifth genotype. Evolutionary analysis suggests JEV originated in the Indonesia-Malaysia region around the mid-1500s.

Area of Science:

  • Virology
  • Molecular Evolution
  • Epidemiology

Background:

  • Japanese encephalitis virus (JEV) is a significant global cause of epidemic encephalitis.
  • The evolutionary origins and genetic diversity of JEV remain incompletely understood.
  • Previous studies identified four JEV genotypes, with a potential fifth genotype suggested by limited data.

Purpose of the Study:

  • To determine the complete nucleotide and amino acid sequence of the Muar strain, a putative JEV genotype V isolate.
  • To phylogenetically analyze the Muar strain and compare it with other JEV genotypes.
  • To investigate the evolutionary history and origin of JEV.

Main Methods:

  • Whole-genome sequencing of the JEV Muar strain.
  • Comparative sequence analysis of JEV genomes (nucleotide and amino acid divergence).
  • Phylogenetic analysis to determine JEV genotype classification.
  • Evolutionary rate estimation and molecular clock analysis.

Main Results:

  • The Muar strain represents a distinct fifth genotype of JEV, showing significant sequence divergence from other genotypes.
  • Specific amino acid signatures in the envelope (E) protein, such as E327 Glu, distinguish the Muar strain.
  • Evolutionary analysis indicates JEV originated in the Indonesia-Malaysia region in the mid-1500s.
  • The envelope (E) gene is under strong purifying selection, with no evidence of positive selection among genotypes.

Conclusions:

  • The Muar strain confirms the existence of a fifth JEV genotype.
  • The findings provide insights into the origin and early evolution of JEV in Southeast Asia.
  • Understanding JEV genotype diversity and evolution is crucial for disease control and prevention strategies.

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