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Date: July 21, 2003
Posted by: Environmental Risk Analysis Program <envrisk@cornell.edu>

[1] Background
[2] BBC Report re: Antibodies to WNV in High Proportion of British Birds
[3] Research article: Serological Evidence of WNV in Birds in UK


[1]
BACKGROUND:
A Oct 29 2002 WNV-L posting noted that researchers at the Oxford 
University-based Centre for Ecology and Hydrology had found WNV 
antibodies in non-migratory birds in the UK. These findings suggested 
that WNV was present in the UK (BBC Oct 28, 2002).  Results from this 
research have now been published in the Journal of General Virology 
[3] and discussed in greater depth in a July 19 BBC Report [2].


[2]
BBC REPORT RE: ANTIBODIES TO WNV IN HIGH PROPORTION OF BRITISH BIRDS
Excerpted from ProMED-mail (Id: 20030719.1772) posted July 19, 2003
Source: BBC News Online, July 19, 2003 
http://news.bbc.co.uk/1/hi/sci/tech/3079425.stm

Evidence of the potentially deadly WNV has been found in a high 
proportion of British birds, scientists have revealed. ... Scientists 
at the Centre for Ecology and Hydrology [formerly the NERC Institute 
of Virology] in Oxford tested birds mainly in Cambridgeshire, but 
also in Dorset and South Wales. They found evidence of the virus in 
more than half the birds tested — an "unexpectedly high" proportion, 
BBC science correspondent Christine McGourty said. It was found in 
more than 20 species in all, including crows, magpies, swallows, 
chickens, turkeys, and ducks.

While the birds were healthy and showed no symptoms, scientists did 
detect antibodies to the virus. This indicated the birds had come 
into contact with the virus and that their natural defences had 
successfully fought it
off. It is thought that the virus is being brought into the country 
by migrating birds.

The researchers said there was no immediate threat to humans, but 
warned that climate change might increase the risk. The research, 
published on Sat 19 Jul 2003, comes after increased surveillance 
measures for the virus were introduced in the UK. The chief medical 
officer for England, Sir Liam Donaldson, announced the measures in 
early July, saying the risk to human health was low, but doctors and 
health officials had been urged to be on
the look-out for symptoms.


[3]
RESEARCH ARTICLE: SEROLOGICAL EVIDENCE OF WNV IN BIRDS IN UK
Serological evidence of West Nile virus, Usutu virus and Sindbis 
virus infection of birds in the UK
Alan Buckley,1 Alistair Dawson,2 Stephen R. Moss,1 Shelley A. 
Hinsley,2 Paul E. Bellamy2 and Ernest A. Gould1

1Centre for Ecology and Hydrology Oxford, Institute of Virology and 
Environmental Microbiology, Mansfield Road, Oxford OX1 3SR, UK
2Centre for Ecology and Hydrology, Monkswood, Abbots Ripton, 
Cambridge PE28 2LS, UK

Published in the online advance edition  of the Journal of General 
Virology.  It will appear in the October 2003 print issue of JGV and 
thereafter be available in electronic form on JGV Online. Full text 
can now be accessed from: 
http://www.sgm.ac.uk/JGVDirect/19341/19341a.htm.

ABSTRACT:
The introduction and rapid dispersal of the African flavivirus West 
Nile virus (WNV) throughout North
America, and the high fatality rate due to encephalitis in birds, 
horses, other wildlife species and humans, has attracted major 
attention worldwide.  Usutu virus, another flavivirus, came to 
prominence in 2001, when it was
identified as the agent responsible for a drop in the bird population 
in Austria; previously this encephalitic virus was found only in 
birds and mosquitoes in Africa. Sindbis virus, a pathogenic 
alphavirus that causes arthritis, is widespread throughout Africa, 
Europe, Asia and Australia, infecting a range of arthropods and 
vertebrates and is genetically related to encephalitic viruses in 
North America. Currently there is no evidence that any of these 
viruses cause disease in the UK. Here the presence of virus-specific 
neutralizing antibodies is reported in the sera of resident and 
migrant birds in the UK, implying that each of these viruses is being 
introduced to UK birds, possibly by mosquitoes. This is supported by 
nucleotide sequencing that identified three slightly different 
sequences of WNV RNA in tissues of magpies and a blackbird. The 
detection of specific neutralizing antibodies to WNV in birds 
provides a plausible explanation for the lack of evidence of a 
decrease in the bird population in the UK compared with North 
America. The potential health risk posed to humans and animals by 
these viruses circulating in the UK is discussed."

[ProMED Moderator Comment: The apparent absence of disease in 
arthropod borne virus-infected British
wild birds in contrast to the behavior of introduced West Nile virus 
in North America and Usutu virus in Austria is striking. To what 
extent this phenomenon may be due to genetic differences in the 
virulence of virus
strains, to routes of transmission, or to vector specificity are 
intriguing questions for future analysis. - Mod.CP]

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