OIE Reference Laboratory Reports
Activities in 2011
Name of disease (or topic) for
which you are a designated OIE
Reference Laboratory:
Address of laboratory
Equine viral arteritis
Gluck Equine Research Center
University of Kentucky
Lexington, KY 40546
UNITED STATES OF AMERICA
Tel.:
(+1-859) 218-1094
Fax:
(+1-859) 257-8542
e-mail address:
ptimoney@uky.edu
website:
Name (including Title and
Position) of Head of Laboratory
(Responsible Official):
http://www.ca.uky.edu/gluck/servpoe/as[
Dr Mats Troedsson
Name(including Title and
Position) of OIE Reference
Expert:
Dr Peter Timoney
Name (including Title and
Position) of writer of this report
(if different from above):
Dr Peter Timoney
Annual reports of OIE Reference Centres, 2011
1
Equine viral arteritis
Part I: Summary of general activities related to the disease
1.
2.
Test(s) in use/or available for the specified disease/topic at your laboratory
Test
For
Specificity
Total
rRT-PCR
Nucleic acid detection
Type
30
FAT
Antigen detection
Type
3
VN
Antibody
Type
12,808
RK-13 cell culture
Virus isolation
372
Production and distribution of diagnostic reagents
 OIE approved reference sera, cell lines RK-13 (ATCC CCL 37 and RK13 Kentucky), and an equine
endothelial cell line for equine arteritis virus (EAV) isolation and quantitation, test panels of equine semen and
serum samples.
Type of reagent
Amount supplied nationally
(including for own use)
Amount supplied to other
countries
OIE Approved sera
14 ml
18 ml
Test semen panel
--
--
Test serum panel
20 ml
10 ml
Control positive sera
--
--
RK-13 cell line
550 x 150 cm² flasks
3 x 75 cm² flasks
7,088 x 25 cm² flasks
1 x 75 cm² flask
EEC* cell line
117 x 75 cm² flasks
281 x 25 cm² flasks
--
Reference virus
--
2 x 1 ml
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
While the Reference Laboratory did not organize nor was invited to participate in any international ring trials
in 2011, it maintains contact with the other two OIE designated reference laboratories for EVA whenever
technical concerns/problems over virus detection or antibody determination arise. Furthermore, consultation
takes place with those laboratories over revisions to the Terrestrial Code chapter on EVA as deemed
necessary.
2
Annual reports of OIE Reference Centres, 2011
Equine viral arteritis
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
The Reference Laboratory participates in the interlaboratory check test organized by the USDA’s National
Veterinary Services Laboratory, Ames, IA to confirm its proficiency in EAV VN antibody determination. It
has also participated in a comparison study of the VN test and an experimental cELISA developed by
commercial company in the US. The laboratory conducted an interlaboratory test evaluation for both virus
detection by VI and RT-PCR and VN antibody determination with the CFIA Laboratory, Lethridge, Canada
(participant)
The laboratory was not involved in harmonizing production methods or quality control of vaccines.
4.
Preparation and supply of international reference standards for diagnostic tests or vaccines
The Reference Laboratory has available for distribution OIE Approved Reference sera for EVA and reference
virus. Additionally, panels of test sera and test semen samples are supplied upon request to laboratories wishing to
assess their proficiency in antibody determination or EAV detection by virus isolation and/or PCR assay. A high
passage rabbit kidney cell line (RK-13KY) is also available upon request for both virus isolation and antibody
determination in the VN test. All the foregoing reagents have been prepared by the Reference Laboratory.
The panel of OIE Approved EVA Reference sera was supplied to Germany, Italy and Uruguay (each panel
comprises 1.5 mL x 3 positive serum controls and 1.5 mL x 1 negative serum control). Also, various non-OIE
approved materials have been provided to the following OIE Member country: Uruguay (panel of equine test sera,
10 mL; MLV vaccine against EVA 2 mL; RK-13 ATCC CCL37, high passage Kentucky line 1 x 75 cm2 flask).
5.
Research and development of new procedures for diagnosis and control
Four EVA-related research studies were completed in 2011, two of which have been published and a third has
been written up for publication. The fourth study on the safety and immunogenicity of a modified live virus
vaccine against EVA in yearling colts has been completed but not yet written up for publication. The first study
was undertaken in collaboration with the Frank Duncombe Laboratory, Caen, France and involved evaluation of
two magnetic bead-based viral nucleic acid purification kits and three real-time RT-PCR reagent systems in two
TaqMan assays for EAV detection. The outcome of this study demonstrated that using a magnetic-bead based
nucleic acid extraction method combined with reagents from a one-step QuantiFast rRT-PCR kit, this assay
offered sensitivity equivalent to or slightly higher than virus isolation for detection of EAV in semen. The second
study was undertaken in collaboration with the Dept. of Med. Microbiol., Leiden University Medical Centre,
Leiden, the Netherlands. It characterized the equine humoral antibody response to the non-structural proteins of
EAV. A third study was a collaborative effort with the Swedish University of Agricultural Sciences, Uppsala,
Sweden. It investigated the effect of processing semen from EAV carrier stallions by Single Layer Centrifugation
through a species specific colloid. Although such treatment did significantly reduce infectivity levels in semen,
considerable levels of virus still remained. The fourth study involved a 2-year field trial of a modified live vaccine
against EVA in Standardbred yearlings. It confirmed the safely of the vaccine and its ability to stimulate
protective levels of neutralizing antibodies in the vast majority of vaccinated colts.
6.
Collection, analysis and dissemination of epizootiological data relevant to international disease
control
The Reference Laboratory actively follows up on suspect outbreaks of EVA to obtain material for agent detection
and characterization and to establish any unique epidemiological features of such disease events. Current
information on the epidemiology, prevention and control of EVA continues to be disseminated through various
scientific and industry publications and presentations at regional, national and international meetings. A
serological survey of New World camelids in the US has been completed and the results are being written up for
publication. The goal of the study was to determine whether there was evidence of EAV infection in the
population sampled and if so, could it be linked to abortion in pregnant llamas or alpacas. A very small percentage
of camelids were positive for EAV antibodies and no connection could be established between seropositivity and
abortion. Based on the results of the study, there are no plans to investigate further the possible epidemiological
significance of llamas and alpacas as additional host species of EAV.
Annual reports of OIE Reference Centres, 2011
3
Equine viral arteritis
One notification has been sent to the OIE concerning a group of 19 horses that tested seropositive for VN
antibodies to EAV in a Member State, Germany.
7.
Maintenance of a system of quality assurance, biosafety and biosecurity relevant to the
pathogen and the disease concerned
Since its initial designation as an OIE Reference Center for EVA in the early 1990s, the Laboratory has
functioned/operated under stringent standards in all aspects of specimen handling, performance of tests for agent
detection or antibody determination, maintenance of a comprehensive record keeping system and reporting of test
results. For many years, it has engaged in development/improvement of various diagnostic tests and their
validation as well as evaluation of the safety and efficacy of a modified live vaccine virus for the prevention and
control of EVA and establishment of the carrier state in the mature, sexually intact male, principally the breeding
stallion. Performance of all test procedures is carried out in strict conformity with the methodologies detailed in
the OIE Standards Manual. A comprehensive set of Standard Operating Procedures has been in place for a
significant number of number of years ; these provide detailed information on all aspects of the functioning of the
reference laboratory consistent with the recommendations set out in the OIE Quality Standard and Guidelines for
Veterinary Laboratories: Infectious Diseases (2nd edition, 2008).
8.
Provision of consultant expertise to OIE or to OIE Member Countries
The Reference Center was consulted on a range of scientific and regulatory aspects of EVA by veterinary
regulatory officials, veterinarians, researchers, members of the horse industry including shipping agents from a
number of OIE Member countries. These included: Argentina, Australia, Canada, Chile, Colombia, Germany,
Italy, Mongolia, Mozambique, New Zealand, Peru, Philippines, Uruguay, and the Netherlands.
The designated specialist reviewed and provided advice on proposed revisions to the Animal Health Code chapter
on EVA and contributed to technical papers on improved diagnostic methods specifically the PCR, evaluation of
safety and efficacy of a commercial vaccine against EVA in yearling colts and increasing our understanding of the
epidemiology of EAV as it relates to outbreaks of EVA.
9.
Provision of scientific and technical training to personnel from other OIE Member Countries
The Reference Center provided scientific and technical training in current OIE approved diagnostic tests for EAV
infection to three scientists, one from the Institute of Virology, INTA Castelar, Buenos Aires, Argentina, the
second from the Faculty of Veterinary Medicine, University of Perugia, Perugia, Italy, and the third from the
Swedish University of Agricultural Sciences, Uppsala, Sweden. No formal workshops or technical training courses
were organized in 2011.
10. Provision of diagnostic testing facilities to other OIE Member Countries
Diagnostic services were provided to 6 Member Countries additional to the USA. All but one of the tests carried
out were diagnostic. Submitting countries (number samples tested) included: Argentina (32), Canada (12),
Colombia (15), Germany (57), Peru (3), and the Netherlands (2). Samples for confirmatory testing were received
from Chile (1).
11. Organisation of international scientific meetings on behalf of OIE or other international bodies
None.
12. Participation in international scientific collaborative studies
Details of three collaborative research studies that were undertaken in 2011 are provided under point 5.
4
Annual reports of OIE Reference Centres, 2011
Equine viral arteritis
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
Go YY, Cook D, Timoney PJ, Bailey E, Balasuriya UBR (2011) Genome wide association study to identify the
genetic determinants of susceptibility of horses to equine arteritis virus infection, 12 th International Nidovirus
Symposium, Traverse City, MI, June 4-9, 2011, pp. 52-53.
Go YY, Li Y, Chen Z, Yoo D, Timoney PJ, Snijder EJ, Fang Y, Balasuriya UBR (2011) Equine arteritis virus
does not induce type I interferon α/β production in equine endothelial cells: identification of nonstructural protein
1 as a main interferon antagonist, 12th International Nidovirus Symposium, Traverse City, MI, June 4-9, 2011, pp.
54-55.
Go YY, Timoney PJ, Snijder EJ, Balasuriya UBR (2011) Humoral antibody response to the nonstructural proteins
of equine arteritis virus, 12th International Nidovirus Symposium, Traverse City, MI, June 4-9, 2011, pp. 81-82.
Go YY, Fulgencio JQ, Campos JR, Henney P, Cook RF, Timoney PJ, Balasuriya UBR (2011) In vitro
susceptibility or resistance of equine CD3+ T lymphocytes to equine arteritis virus: is there a correlation with
clinical outcome to infection in horses?, 12th International Nidovirus Symposium, Traverse City, MI, June 4-9,
2011, p. 98.
Shuck KM, Miszczak F, Lu Z, Go YY, Zhange J, Sells S, Vabret A, Pronost S, Fortier G, Timoney PJ, Balasuriya
UBR (2011) Evaluation of two magnetic bead-based viral nucleic acid purification kits and three real-time RTPCR reagent systems in two TaqMan assays compared to virus isolation for equine arteritis virus detection in
semen, 12th International Nidovirus Symposium, Traverse City, MI, June 4-9, 2011, p. 103.
Perglione CO, Miño, Córdoba M, Echeverria G, Timoney PJ, Tordoya S, Darqui F, Metz G, Becerra L, Serena M,
Vissani A, Uncal L, Dayraut J, Barrandeguy M (2011) Overview and molecular epidemiology of the 2010 equine
viral arteritis outbreak in Argentina, 12th International Nidovirus Symposium, Traverse City, MI, June 4-9, 2011,
p. 100.

Scientific publications in peer-reviewed journals
Broaddus CC, Balasuriya UBR, Richards J, Timoney PJ, Funk RA and Holyoak GR (2011) Evaluation of the
Safety of Vaccinating Mares Against Equine Viral Arteritis in Mid or Late Pregnancy or during the Immediate
Postpartum Period. J Am Vet Med Assoc, 238:741-750.
Summers-Lawyer AK, Go YY, Lu Z, Timoney PJ, McCue PM, Zhang J, Shuck KM and Bruemmer J (2011)
Response of Stallions to Primary Immunization with a Modified Live Equine Viral Arteritis Vaccine. J Equine Vet
Sci, 31:129-138.
Go YY, Snijder EJ, Timoney PJ and Balasuriya UBR (2011) Characterization of Equine Humoral Antibody
Response to the Nonstructural Proteins of Equine Arteritis Virus. Clinical and Vaccine Immunology, 18:268-279.
Broaddus CC, Balasuriya UBR, White J, Timoney PJ, Makloski C, Torrisi K, Payton M and Holyoak GR (2011)
Infection of Embryos following insemination of Donor Mares with Equine Arteritis Virus Infective Semen.
Theriogen, 76:47-60.
Perglione CO, Cordoba M, Echeverria G, Timoney PJ, Tordoya S, Darqui F, Metz G, Mino S, Becerra L, Serena
M, Vissani A, Gonzalez T, Silvestrini M, Corva S, Uncal L, Dayraut J, Badaracco A and Barrandeguy M (2010)
Equine Viral Arteritis Outbreak in Argentina. Proc 114th Annual Meeting of the USAHA, pp. 320-329.
Miszczak F, Shuck KM, Lu Z, Go YY, Zhang J, Sells S Vabret A, Pronost S, Fortier G, Timoney PJ and
Balasuriya UBR (2011) Evaluation of Two Magnetic Bead-Based Viral Nucleic Acid Purification Kits and Three
Real-time RT-PCR Reagent Systems in Two TaqMan Assays for Equine Arteritis Virus Detection. J Clin
Microbiol, 49:3694-3696.

Other communications
Timoney PJ (2011) Equine Viral Arteritis. Equine Reproduction, 2nd Ed., McKinnon, Squires, Vaala, and Varner
(eds.), pp. 2391-2398.
_______________
Annual reports of OIE Reference Centres, 2011
5