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Volume 18, Number 5—May 2012

Characterization of Virulent West Nile Virus Kunjin Strain, Australia, 2011

Melinda J. Frost1, Jing Zhang1, Judith H. Edmonds1, Natalie A. Prow1, Xingnian Gu, Rodney Davis, Christine Hornitzky, Kathleen E. Arzey, Deborah Finlaison, Paul Hick, Andrew Read, Jody Hobson-Peters, Fiona J. May, Stephen L. Doggett, John Haniotis, Richard C. Russell, Roy A. Hall2, Alexander A. Khromykh2, and Peter D. Kirkland2Comments to Author 
Author affiliations: Elizabeth Macarthur Agriculture Institute, Menangle, New South Wales, Australia (M.J. Frost, J. Zhang, X. Gu, R. Davis, C. Hornitzky, K.E. Arzey, D. Finlaison, P. Hick, A. Read, P.D. Kirkland); The University of Queensland, St Lucia, Queensland, Australia (J.H. Edmonds, N.A Prow, J. Hobson-Peters, F.J. May, R.A. Hall, A. A. Khromykh); University of Sydney and Westmead Hospital, Westmead, New South Wales, Australia (S.L. Doggett, J. Haniotis, R.C. Russell)

Main Article

Table 3

Neutralizing titers of serum samples from WNV–infected horses against 3 WNV strains, Australia, 2011*

Horse serum samples % Inhibition of CPE/growth†
WNVNSW2011, 100 infectious units
  WNVKUN, 26 infectious units
  WNVNY99, 32 infectious units
80‡ 100§ 80 100 80 100
1 <20 <20   <20 <20   <20 <20
2 <20 <20   <20 <20   <20 <20
3 <20 <20   <20 <20   <20 <20
4 <20 <20   <20 <20   <20 <20
5 <20 <20   <20 <20   <20 <20
04 640 320   1,280 1,280   640 320
06 320 160   640 640   1,280 160
08 320 320   1,280 1,280   640 640
28 320 320   640 640   320 320
36 320 160   640 640   320 640
111473 80 20   640 320   160 160
104714 320 80   640 640   640 640
110910 80 40   160 160   160 160
98727 40 40   160 160   80 80
1 160 40   640 40   320 320
2 320 160   1,280 640   160 160
3 80 160   320 320   640 640
4 40 20   160 160   320 320
5 320 80   1,280 320   640 640
mAb 3.91D‡‡ >2,560 >2,560   >2,560 >2,560   >2,560 >2,560

*Determined, as described (14), by microneutralization assay in Vero cells. WNV, West Nile virus; CPE, cytopathic effect; NSW, New South Wales; KUN, Kunjin; NY, New York; NT, Northern Territory; mAb, monoclonal antibody.
Boldface indicates serum samples with >4-fold difference in titer between virus strains.
‡Determined by using a microscope to assess the level of CPE in each well compared with that in control wells.
§Determined by the absence of viral antigen in the cell monolayer of each well when tested with a WNV-reactive mAb in ELISA.
¶Samples from uninfected horses.
#Samples from horses infected with WNV during the 2011 outbreak in New South Wales, Australia.
**Samples from horses infected with WNVKUN in Northern Territory, Australia.
††Samples from horses infected with WNV in the United States.
‡‡This mAb has potent WNV-neutralizing activity (11).

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  1. Russell  RC, Dwyer  DE. Arboviruses associated with human disease in Australia. Microbes Infect. 2000;2:1693704. DOIPubMedGoogle Scholar
  2. Mackenzie  JS, Lindsay  MD, Coelen  RJ, Broom  AK, Hall  RA, Smith  DW. Arboviruses causing human disease in the Australasian zoogeographic region. Arch Virol. 1994;136:44767. DOIPubMedGoogle Scholar
  3. Hall  RA, Broom  AK, Smith  DW, Mackenzie  JS. The ecology and epidemiology of Kunjin virus. Curr Top Microbiol Immunol. 2002;267:25369. DOIPubMedGoogle Scholar
  4. Badman  RT, Campbell  J, Aldred  J. Arbovirus infection in horses—Victoria 1984. Commun Dis Intell. 1984;17:56.
  5. Ostlund  EN, Crom  RL, Pedersen  DD, Johnson  DJ, Williams  WO, Schmitt  BJ. Equine West Nile encephalitis, United States. Emerg Infect Dis. 2001;7:6659. DOIPubMedGoogle Scholar
  6. Russell  RC, Doggett  SL, Clancy  J, Haniotis  J, Patsouris  K, Hueston  L, Arbovirus and vector surveillance in NSW, 1997–2000. Arbovirus Research in Australia. 2001;8:30413.
  7. Khromykh  AA, Sedlak  PL, Westaway  EG. Complementation analysis of the flavivirus Kunjin NS5 gene reveals an essential role for translation of its N-terminal half in RNA replication. J Virol. 1999;73:924755.PubMedGoogle Scholar
  8. Audsley  M, Edmonds  J, Liu  W, Mokhonov  V, Mokhonova  E, Melian  EB, Virulence determinants between New York 99 and Kunjin strains of West Nile virus. Virology. 2011;414:6373. DOIPubMedGoogle Scholar
  9. Hall  RA, Broom  AK, Hartnett  AC, Howard  MJ, Mackenzie  JS. Immunodominant epitopes on the NS1 protein of MVE and KUN viruses serve as targets for a blocking ELISA to detect virus-specific antibodies in sentinel animal serum. J Virol Methods. 1995;51:20110. DOIPubMedGoogle Scholar
  10. Eiden  M, Vina-Rodriguez  A, Hoffmann  B, Ziegler  U, Groschup  M. Two new real-time quantitative reverse transcription polymerase chain reaction assays with unique target sites for the specific and sensitive detection of lineages 1 and 2 West Nile virus strains. J Vet Diagn Invest. 2010;22:74853. DOIPubMedGoogle Scholar
  11. Adams  SC, Broom  AK, Sammels  LM, Hartnett  AC, Howard  MJ, Coelen  RJ, Glycosylation and antigenic variation among Kunjin virus isolates. Virology. 1995;206:4956. DOIPubMedGoogle Scholar
  12. Hall  RA, Kay  BH, Burgess  GW, Clancy  P, Fanning  ID. Epitope analysis of the envelope and non-structural glycoproteins of Murray Valley encephalitis virus. J Gen Virol. 1990;71:292330. DOIPubMedGoogle Scholar
  13. Hall  RA, Burgess  GW, Kay  BH, Clancy  P. Monoclonal antibodies to Kunjin and Kokobera viruses. Immunol Cell Biol. 1991;69:479. DOIPubMedGoogle Scholar
  14. Hobson-Peters  J, Toye  P, Sanchez  MD, Bossart  KN, Wang  LF, Clark  DC, A glycosylated peptide in the West Nile virus envelope protein is immunogenic during equine infection. J Gen Virol. 2008;89:306372. DOIPubMedGoogle Scholar
  15. Hall  RA, Tan  SE, Selisko  B, Slade  R, Hobson-Peters  J, Canard  B, Monoclonal antibodies to the West Nile virus NS5 protein map to linear and conformational epitopes in the methyltransferase and polymerase domains. J Gen Virol. 2009;90:291222. DOIPubMedGoogle Scholar
  16. May  FJ, Davis  CT, Tesh  RB, Barrett  AD. Phylogeography of West Nile virus: from the cradle of evolution in Africa to Eurasia, Australia, and the Americas. J Virol. 2011;85:296474. DOIPubMedGoogle Scholar
  17. Guindon  S, Gascuel  O. A simple, fast, and accurate algorithm to estimate large phylogenies by maximum likelihood. Syst Biol. 2003;52:696704. DOIPubMedGoogle Scholar
  18. Prow  NA, May  FJ, Westlake  DJ, Hurrelbrink  RJ, Biron  RM, Leung  JY, Determinants of attenuation in the envelope protein of the flavivirus Alfuy. J Gen Virol. 2011;92:228696. DOIPubMedGoogle Scholar
  19. Lanciotti  RS, Roehrig  JT, Deubel  V, Smith  J, Parker  M, Steele  K, Origin of the West Nile virus responsible for an outbreak of encephalitis in the northeastern United States. Science. 1999;286:23337. DOIPubMedGoogle Scholar
  20. Scherret  JH, Poidinger  M, Mackenzie  JS, Broom  AK, Deubel  V, Lipkin  WI, The relationships between West Nile and Kunjin viruses. Emerg Infect Dis. 2001;7:697705. DOIPubMedGoogle Scholar
  21. Hall  RA, Nisbet  DJ, Pham  KB, Pyke  AT, Smith  GA, Khromykh  AA. DNA vaccine coding for the full-length infectious Kunjin virus RNA protects mice against the New York strain of West Nile virus. Proc Natl Acad Sci U S A. 2003;100:104604. DOIPubMedGoogle Scholar
  22. Chang  DC, Liu  WJ, Anraku  I, Clark  DC, Pollitt  CC, Suhrbier  A, Single-round infectious particles enhance immunogenicity of a DNA vaccine against West Nile virus. Nat Biotechnol. 2008;26:5717. DOIPubMedGoogle Scholar
  23. Beasley  DW, Li  L, Suderman  MT, Barrett  AD. Mouse neuroinvasive phenotype of West Nile virus strains varies depending upon virus genotype. Virology. 2002;296:1723. DOIPubMedGoogle Scholar
  24. Laurent-Rolle  M, Boer  EF, Lubick  KJ, Wolfinbarger  JB, Carmody  AB, Rockx  B, The NS5 protein of the virulent West Nile virus NY99 strain is a potent antagonist of type I interferon-mediated JAK-STAT signaling. J Virol. 2010;84:350315. DOIPubMedGoogle Scholar
  25. Brault  AC, Huang  CY, Langevin  SA, Kinney  RM, Bowen  RA, Ramey  WN, A single positively selected West Nile viral mutation confers increased virogenesis in American crows. Nat Genet. 2007;39:11626. DOIPubMedGoogle Scholar
  26. Wright  PJ. Envelope protein of the flavivirus Kunjin is apparently not glycosylated. J Gen Virol. 1982;59:2938. DOIPubMedGoogle Scholar
  27. Hanna  SL, Pierson  TC, Sanchez  MD, Ahmed  AA, Murtadha  MM, Doms  RW. N-linked glycosylation of West Nile virus envelope proteins influences particle assembly and infectivity. J Virol. 2005;79:1326274. DOIPubMedGoogle Scholar
  28. Bingham  J, Lunt  RA, Green  DJ, Davies  KR, Stevens  V, Wong  FY. Experimental studies of the role of the little raven (Corvus mellori) in surveillance for West Nile virus in Australia. Aust Vet J. 2010;88:20410. DOIPubMedGoogle Scholar

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1These authors contributed equally to the major technical aspects of this research.

2These authors served as joint senior authors.

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Page updated: April 12, 2012
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