Fwd: West Nile virus, sentinel birds - UK

International Society for Infectious Diseases
<http://www.isid.org >

Source: Virology Journal 2006, *3**:*71
< http://www.virologyj.com/content/3/1/71 >

Detection of seroconversion to West Nile virus, Usutu virus and
Sindbis virus in UK sentinel chickens
Alan Buckley /1  , Alistair Dawson /2   and Ernest A Gould /1
1/ CEH Oxford, Mansfield Road, Oxford OX1 3SR, UK
2/ CEH Monks Wood, Abbots Ripton, Huntingdon, Cambridgeshire PE28 2LS, UK

Summary. We previously reported evidence of West Nile virus (WNV)
circulation in UK birds, probably introduced by migratory birds from
overseas. We now demonstrate WNV-specific seroconversion in sentinel
chickens raised on an English farm. Maternal neutralizing antibodies
to WNV in hatchlings declined within 3 weeks. During the following
months, healthy chickens developed WNV neutralizing antibodies that
were confirmed by immunoblotting and indirect immunofluorescence
tests using WNV antigens. The proportion of seropositive chickens was
higher for WNV than for Usutu virus or Sindbis virus. Attempts to
isolate infectious virus or to detect viral RNA in the sera, failed.

Although no virus isolates were made nor WNV RNA sequences detected,
this paper provides additional strong serological evidence for the
presence of West Nile virus (WNV), or a flavivirus closely related to
it, in the UK.  The authors reported  previously on the presence of
WNV neutralizing antibody and small fragments of RNA with sequences
corresponding to WNV  (Journal of General Virology for October 2003
(Buckley A, Dawson A, Moss SR, Hinsley SA, Bellamy PE, Gould EA.
Serological evidence of West Nile virus, Usutu virus and Sindbis
virus infection of birds in the UK.
< http://www.sgm.ac.uk/JGVDirect/19341/19341a.htm >). The current paper
reports the development of specific antibody in prospectively
monitored sentinel chickens.  The seroconversions in the absence of
human or equine cases is interesting, and suggests that prospective
monitoring of humans, animals and mosquitoes for additional evidence
of WNV transmission would be worthwhile, and provide isolates of the
virus for comparison with other WNV isolates.  The question of
endemicity of WNV versus reintroduction into the UK remains open.