OIE Reference Laboratory Reports
Activities in 2011
Name of disease (or topic) for
which you are a designated OIE
Reference Laboratory:
Caprine arthritis/encephalitis
and
maedi-visna
Address of laboratory:
Animal Disease Research Unit,
Agricultural Research Service,
U.S. Department of Agriculture,
3003 ADBF, Washington State University,
Pullman WA 99164-6630
UNITED STATES OF AMERICA
Tel.:
1-509-335-7407 (SNW)
1-509-335-6022 (DPK)
1-509-335-8328
Fax:
e-mail address:
swhite@vetmed.wsu.edu
dknowles@vetmed.wsu.edu
website:
Name (including Title and
Position) of Head of Laboratory
(Responsible Official):
Name (including Title and
Position) of OIE Reference
Expert:
Donald P. Knowles,
Research Leader & Professor
Donald P. Knowles,
Research Leader &
Professor of Veterinary Microbiology
and Pathology
Name (including Title and
Position) of writer of this report
(if different from above):
Annual reports of OIE Reference Centres, 2011
1
Caprine arthritis/encephalitis & maedi-visna
Part I: Summary of general activities related to the disease
1.
Test(s) in use/or available for the specified disease/topic at your laboratory
The following serologic assays are performed for CAEV/MVV and available: AGID, ELISA, cELISA and
Immunoprecipitation
2.
2
Test
For
Specificity
Total
AGID
Antibody
CAEV and/or MVV whole
antigen
0
ELISA
Antibody
CAEV whole antigen, MVV
whole antigen, MVV
recombinant tm90, p28 or
tm90-p28 fusion protein
~100
cELISA
Anti-CAEV/MVV gp 135
epitope
CAEV gp135 antigen
~3000
Immunoprecipitation
Antibody
S-35 methionine/cysteine
labelled CAEV & MVV
whole antigen
10
Western blot (Immunoblot)
Antibody
MVV whole antigen
150
GSM or OCP cell co-culture
with other cells or primary
GSM or OCP isolation
Virus Isolation
CAEV, MVV
0
PCR
Virus genome detection
CAEV and MVV ENV, MVV
LTR
3000
IFA
Antigen
CAEV or MVV p28
0
Immunohistochemistry
Antigen
CAEV or MVV p28
10
In situ DNA hybridization
Virus genome detection
CAEV or MVV GAG
0
Production and distribution of diagnostic reagents
Type of reagent
Amount supplied nationally
(including for own use)
Amount supplied to other
countries
Positive control serum
250ml
0 ml
Small ruminant lentivirus strains
50 ml OPPV Dubois strain LMH17
0 ml
Annual reports of OIE Reference Centres, 2011
Caprine arthritis/encephalitis & Maedi visna
Part II: Activities specifically related to the mandate
of OIE Reference Laboratories
3.
International harmonisation and standardisation of methods for diagnostic testing or the
production and testing of vaccines
a)
Establishment and maintenance of a network with other OIE Reference Laboratories
designated for the same pathogen or disease and organisation of regular inter-laboratory
proficiency testing to ensure comparability of results
Vaccines are not currently available for small ruminant lentiviruses, we continue to work with OIE and
collaborators (national and international) to vevelo an ELISA as a prescribed test for serological detection of
persistent small ruminant lentivirus infection.
b)
Organisation of inter-laboratory proficiency testing with laboratories other than OIE
Reference Laboratories for the same pathogens and diseases to ensure equivalence of
results
None during 2011
4.
5.
Preparation and supply of international reference standards for diagnostic tests or vaccines
Reference standard test
Type of reagent
Western blot analysis
OPPV WLC1, CAEV-63, CAEV-CO, Sheep negative control serum
OPPV quantitative real time PCR
Plasmid control containing OPPV envelope
cELISA
Sheep negative control serum
Research and development of new procedures for diagnosis and control
Through the addition of Dr Stephen White, we are embarking on research concerning genetic control of
OPPV/CAEV infection and transmission. Please see the publication below.
6.
Collection, analysis and dissemination of epizootiological data relevant to international disease
control
Molecular Epidemiology Survey: Using a ewe flock in Idaho, USA, we asked whether proviral envelope (env) and
the long terminal repeat (ltr) were genetically similar between dam-daughter pairs. This study occurred from a
2008 bleed of the Idaho, USA ewe flock. We showed that dam to daughter maternal transmission of OPPV occurs
10-14% of the time whereas the majority (86-90%) of transmission is non-maternal or horizontal transmission.
Evaluation of sexual and/or paternal transmission routes, which are included in this non-maternal transmission,
will commence at a later date.
7.
Maintenance of a system of quality assurance, biosafety and biosecurity relevant to the
pathogen and the disease concerned
We have provided consultant expertise to research persons in Argentina, Russia, Ethiopia, Australia, Canada,
United Kingdom, and the Netherlands. We have worked with OIE working groups to improve the chapter on
MVV/CAEV.
Annual reports of OIE Reference Centres, 2011
3
Caprine arthritis/encephalitis & maedi-visna
8.
Provision of consultant expertise to OIE or to OIE Member Countries
Not requested during 2011
9.
Provision of scientific and technical training to personnel from other OIE Member Countries
Not requested during 2011
10. Provision of diagnostic testing facilities to other OIE Member Countries
Not requested during 2011
11. Organisation of international scientific meetings on behalf of OIE or other international bodies
Not requested during 2011
12. Participation in international scientific collaborative studies
We continue our informal collaborations with Dr Lluis Lujan at the Universidad de Zaragoza in Zaragoza, Spain,
Dr Gabi Obexer-Ruff at the at the Institute of Animal Genetics at the University of Berne in Berne, Switzerland
and Dr Giuseppe Bertoni at the Institute of Veterinary Virology at the University of Bern in Berne, Switzerland.
We collaborate with Dr Keith Ballingall at Moredun Research Institute in Scotland, UK.
13. Publication and dissemination of information relevant to the work of OIE (including list of
scientific publications, internet publishing activities, presentations at international conferences)

Presentations at international conferences and meetings
Not during 2011

Scientific publications in peer-reviewed journals
Heaton, MP, Clawson, ML, Chitko-Mckown, CG, Leymaster, KA, Smith, TP, Harhay, GP, White, SN,
Herrmann-Hoesing, LM, Mousel, MR, Lewis, GS, Kalbfleisch, TS, Keen, JE and Laegreid, WW. (2012)
Reduced lentivirus susceptibility in sheep with TMEM 154 mutations, PLoS Genet. 2012 Jan:8(1):e1002467.
Epub 2012 Jan 26

Other communications
None during 2011
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4
Annual reports of OIE Reference Centres, 2011