TY - JOUR
T1 - Virulence and evolution of West Nile Virus, Australia, 1960-2012
AU - Prow, Natalie A.
AU - Edmonds, Judith H.
AU - Williams, David T.
AU - Setoh, Yin X.
AU - Bielefeldt-Ohmann, Helle
AU - Suen, Willy W.
AU - Hobson-Peters, Jody
AU - van den Hurk, Andrew F.
AU - Pyke, Alyssa T.
AU - Hall-Mendelin, Sonja
AU - Northill, Judith A.
AU - Johansen, Cheryl A.
AU - Warrilow, David
AU - Wang, Jianning
AU - Kirkland, Peter D.
AU - Doggett, Stephen
AU - Andrade, Christy C.
AU - Brault, Aaron
AU - Khromykh, Alexander A.
AU - Hall, Roy A.
PY - 2016/8/1
Y1 - 2016/8/1
N2 - Worldwide, West Nile virus (WNV) causes encephalitis in humans, horses, and birds. The Kunjin strain of WNV (WNVKUN) is endemic to northern Australia, but infections are usually asymptomatic. In 2011, an unprecedented outbreak of equine encephalitis occurred in southeastern Australia; most of the ≈900 reported cases were attributed to a newly emerged WNVKUN strain. To investigate the origins of this virus, we performed genetic analysis and in vitro and in vivo studies of 13 WNVKUN isolates collected from different regions of Australia during 1960-2012. Although no disease was recorded for 1984, 2000, or 2012, isolates collected during those years (from Victoria, Queensland, and New South Wales, respectively) exhibited levels of virulence in mice similar to that of the 2011 outbreak strain. Thus, virulent strains of WNVKUN have circulated in Australia for ≥ 30 years, and the first extensive outbreak of equine disease in Australia probably resulted from a combination of specific ecologic and epidemiologic conditions.
AB - Worldwide, West Nile virus (WNV) causes encephalitis in humans, horses, and birds. The Kunjin strain of WNV (WNVKUN) is endemic to northern Australia, but infections are usually asymptomatic. In 2011, an unprecedented outbreak of equine encephalitis occurred in southeastern Australia; most of the ≈900 reported cases were attributed to a newly emerged WNVKUN strain. To investigate the origins of this virus, we performed genetic analysis and in vitro and in vivo studies of 13 WNVKUN isolates collected from different regions of Australia during 1960-2012. Although no disease was recorded for 1984, 2000, or 2012, isolates collected during those years (from Victoria, Queensland, and New South Wales, respectively) exhibited levels of virulence in mice similar to that of the 2011 outbreak strain. Thus, virulent strains of WNVKUN have circulated in Australia for ≥ 30 years, and the first extensive outbreak of equine disease in Australia probably resulted from a combination of specific ecologic and epidemiologic conditions.
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U2 - 10.3201/eid2208.151719
DO - 10.3201/eid2208.151719
M3 - Article
C2 - 27433830
AN - SCOPUS:84978708718
VL - 22
SP - 1353
EP - 1362
JO - Emerging Infectious Diseases
JF - Emerging Infectious Diseases
SN - 1080-6040
IS - 8
ER -