From:
"Sukie Crandall"
Date: 2007-10-26 04:26:26 UTC
Subject: [ferrethealth] Re: New work on how CDV jumps across species
To: ferrethealth@yahoogroups.com
Using Eurekalert! I found the press release on this study from the Universi=
ty of Leeds:
http://reporter.leeds.ac.uk/press_releases/current/distemper.htm
Since it is a press release I can carry it over for you:
BEGIN QUOTE
25 October 2007
Research sheds new light on how diseases jump across species
Researchers at the University of Leeds have made a breakthrough in understa=
nding a virus
which poses one of the greatest global disease threats to wild carnivores i=
ncluding lions,
African wild dogs and several types of seal.
The discovery of how canine distemper Virus (CDV) jumps across and infects =
different
species of carnivores could lead to a more effective monitoring and control=
of the virus.
Whilst these `pathogen jumps' across species are quite common, very little =
is known about
the process of how viruses takes hold and become established in new host sp=
ecies.
CDV is passed through close contact from domestic and feral dogs causing ep=
idemics that
often result in mass mortalities =96 and is pushing some species to the bri=
nk of extinction
(2).
"The virus needs to bind to a specific receptor on cells in the host in ord=
er to infect it,"
explains lead researcher, PhD student Alex McCarthy, from the University's =
Faculty of
Biological Sciences. "But the sequences of receptors vary between species, =
so a virus from
one species shouldn't be able recognise and infect the cells of other speci=
es."
By analysing the virus' genetic sequence in both dog and wild carnivore spe=
cies, the
research team were able to prove that two key parts of a CDV protein specif=
ically involved
in receptor recognition had evolved during the host jumps, where as the res=
t of the
protein showed very few changes among viruses from different species.
"It was a very satisfying moment when our ideas proved correct," says McCar=
thy. "The
results really screamed out at us. They were so clear-cut, we think it's hi=
ghly likely that
pathogen evolution is a much more general mechanism in cross-species transm=
ission of
viruses than anyone imagined."
The findings could lead on to new antiviral therapies that are targeted at =
the binding
mechanism, to prevent the virus from taking hold, rather than trying to era=
dicate it once
it's in the host's system.
Current conservation policies include vaccination of wild animal population=
s, but this is
not appropriate for logistical or biological reasons for most species. Alte=
rnative strategies
include vaccination of neighbouring domestic and feral dog populations, whi=
ch prevents
CDV circulating in dogs and therefore limits transmission to wildlife. Cull=
ing the
surrounding domestic reservoir species, such as dogs, is also an option, bu=
t this is more
controversial because its efficacy can be questionable and because of the i=
mpact this can
have on support from local communities for wider conservation efforts.
The spread and incidences of CDV epidemics are increasing, due to globalisa=
tion and the
rise in the domestic and feral dog populations associated with growing huma=
n
populations, especially where these impinge on previously undisturbed habit=
ats.
"CDV in wild carnivore populations is usually fatal" says McCarthy. "So as =
well as the
possibility of developing new therapies, the techniques used in this resear=
ch offer a way of
predicting when local virus isolates may become capable of causing a full b=
lown epidemic
in species of conservation concern."
The research could have similar implications for developing new therapies f=
or pathogenic
diseases that have successfully crossed species to humans. Additionally, th=
e team believes
that the phenomenon may be involved in the emergence of many new, previousl=
y species-
specific diseases that have been able to infect new host species, such as S=
ARS, Hendra and
Nipah Virus.
Further information:
Jo Kelly, campuspr Ltd. Tel : 0113 2589880, Mob: 01980 267756
Email: jokelly@campuspr.co.uk
Guy Dixon, University of Leeds press office. Tel : 0113 343 8299
Email: g.dixon@leeds.ac.uk
Notes to editors:
1. Species affected by CDV include lions, spotted hyenas, African wild dogs=
and several
species of seals. The study included virus sequences from a range of carniv=
ore species
including ferrets, leopard, racoons, mink, panda, red panda, javelina, foxe=
s, Baikal &
Caspian seals.
2. In the case of Caspian seals (the world's smallest seal) a series of CDV=
epidemics over
the last 10 years has each seen up to 10,000 animals die =96 out of a total=
population of
only 120,000. CDV is also thought to have been involved in the extinction o=
f the
Tasmanian tiger and the rare black-footed ferret (later successfully re-int=
roduced to the
wild from a captive breeding programme).
3. The research paper is published online in the latest issue of Proceeding=
s of the Royal
Society B. Pathogen evolution and disease emergence in carnivores
Alex J. McCarthy, Marie-Anne Shaw and Simon J. Goodman
Institute of Integrative and Comparative Biology, Faculty of Biological Sci=
ences, University
of Leeds.
4. CDV is in the same family of viruses as measles. It is also closely rela=
ted to, but distinct
from, Phocine Distemper virus (PDV) which has caused two mass die offs of h=
arbour seals
in the North Sea (1988 and 2002).
5. The University of Leeds' Faculty of Biological Sciences is one of the la=
rgest in the UK,
with nearly 150 academic staff and over 400 postdoctoral fellows and postgr=
aduate
students. The Faculty's current active research grant portfolio is around =
=A360M and funders
include charities, Research Councils, the European Union and industry. The =
Faculty has an
outstanding research record and all major units of assessment were awarded =
Grade 5 in
the last government (HEFCE) Research Assessment Exercise. www.fbs.leeds.ac.=
uk
END QUOTE
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/ferrethealth/
<*> Your email settings:
Individual Email | Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/ferrethealth/join
(Yahoo! ID required)
<*> To change settings via email:
mailto:ferrethealth-digest@yahoogroups.com
mailto:ferrethealth-fullfeatured@yahoogroups.com
<*> To unsubscribe from this group, send an email to:
ferrethealth-unsubscribe@yahoogroups.com
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/