Genetic determinants of virulence in pathogenic lineage 2 West Nile virus strains

Emerg Infect Dis. 2008 Feb;14(2):222-30. doi: 10.3201/eid1402.070457.


We determined complete genome sequences of lineage 2 West Nile virus (WNV) strains isolated from patients in South Africa who had mild or severe WNV infections. These strains had previously been shown to produce either highly or less neuroinvasive infection and induced genes similar to corresponding highly or less neuroinvasive lineage 1 strains in mice. Phylogenetic and amino acid comparison of highly and less neuroinvasive lineage 2 strains demonstrated that the nonstructural genes, especially the nonstructural protein 5 gene, were most variable. All South African lineage 2 strains possessed the envelope-protein glycosylation site previously postulated to be associated with virulence. Major deletions existed in the 3 noncoding region of 2 lineage 2 strains previously shown to be either less or not neuroinvasive relative to the highly neuroinvasive strains sequenced in this study.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Genetic Variation*
  • Genome, Viral
  • Genotype
  • Humans
  • Mice
  • Molecular Sequence Data
  • Mutation
  • Phylogeny
  • Sequence Analysis, DNA
  • South Africa
  • Viral Envelope Proteins / genetics
  • Viral Nonstructural Proteins / genetics*
  • Virulence / genetics
  • West Nile Fever / virology*
  • West Nile virus / classification
  • West Nile virus / genetics
  • West Nile virus / pathogenicity*


  • Viral Envelope Proteins
  • Viral Nonstructural Proteins

Associated data

  • GENBANK/EF429197
  • GENBANK/EF429198
  • GENBANK/EF429199
  • GENBANK/EF429200