Equine Herpesvirus Myeloencephalopathy: Diagnostic Information

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Equine herpesvirus-1 is associated with several disease syndromes including abortion, neonatal septicemia, upper respiratory tract disease and a neuropathogenic form known as equine herpesvirus myeloencephalopathy (EHM). EHM is not a new disease and is reported sporadically throughout the world. There is recent concern, however, over emergence of a mutant strain of the virus (nEHV-1) that is more virulent in its ability to cause the neuropathogenic form of EHV-1 disease1. This increased virulence has been expressed in outbreaks of EHM in several countries with a higher than previously reported incidence of morbidity and mortality. A concise description of equine herpesvirus-1 disease, including the neuropathogenic form, recently appeared in Alberta Agriculture’s Animal Health Forum, Vol. 13, Issue 1, February, 20082.

Because of the concern over the potential to see this disease in Alberta horses, both on farms and at events where horses congregate, the information in the table below is provided to assist practitioners with accessing rapid and effective diagnostic laboratory help in the event they suspect this disease. This table also appears on the AVMA website on the home page after member log in3. The table is self-explanatory but if questions or concerns arise, please do not hesitate to call the contact people.

EHV-1 Diagnostics: May 2009; Alberta information addeded December 2011

PCRSerologyContactShipping AddressSubmission FormHours
ABIdexx Code EQHVD (Equine Herpes Type 1-Type 4 real-time PCR).
Sample: nasal swab (sterile, plastic stemmed swab placed in a sterile red top tube- NO culture media) OR whole EDTA blood (7 mL purple top tube). Can also submit tissue samples from abortions/mortalities (cerebrospinal fluid, brain/spinal cord, lung, liver, thymus, spleen, adrenal gland, placenta). Can distinguish between EHV-1 and 4, as well as nEHV-1.
Cost: $85.95 per sample (TAT 1-3 days).
Idexx code EHV1/4.
Paired sera. Test can differentiate EHV-1 and EHV-4, but not nEHV-1. Titers may not be high, even in acute cases.
Cost: $27.95 per test (TAT 7-14 days).
Idexx customer service center (780-437-8808) to redirect to equine expert.Idexx Laboratories.
Edmonton: 8131 Roper Rd, Edmonton, AB T6E 6S4
Calgary: Unit 19, 5080 - 12A ST SE, Calgary, AB, T2G 5K9
Vet Connect (on-line) submission or call lab for submission forms.Variable by lab.
ONNasal swab*, buffy coat (20 ml EDTA blood), tissue (Neuro cases: brain/spinal cord; Respiratory cases: lung; Abortions: lung, liver, thymus, spleen, adrenal glands, placenta). Differentiates EHV-1 from nEHV-1; Cost $65.00/test (sample); gives a +/- answer and differentiates the strain in the same test; TAT 1-3 days after receivedOn paired sera, test does not differentiate EHV-1 from EHV-4,
TAT 7 - 14 days
Dr. Susy Carman
519-824-4120 ext 54551,
Animal Health Laboratory,
Laboratory Services Division,
University of Guelph,
Door P2 Bldg 49, McIntosh Lane
Guelph, ON   N1G 2W1
Indicate in the history that
you would like EHV-1 real-time PCR.
8:15 - 7:00
BCNasal swab*, buffy coat, fresh lung, fresh brain/spinal cord. Cost $37.50 out of province. Will differentiate EHV-1 from nEHV-1 and can sequence virus if needed.For EHV-1 onlyDr. John Robinson
604-556-3003 (main office)
BC Ministry of Agriculture and Food,
Animal Health Centre,
1767 Angus Campbell Rd
Abbotsford, BC   V3G 2M3
then click "Submission Form Mammalian.pdf"
8:30 - 12:00 &
1:00 - 4:30
SKLive horse: nasal swab. Recently dead horse: nasal swab or small piece of nasal mucosa. Test will differentiate EHV-1 from 4; PCR capability to distinguish nEHV-1 currently done as an experimental diagnostic test. Also offer an equine respiratory PCR panel (EHV-1, EHV-4, EIV, Strep equi) for $85.00; use culturette swabs as for bacteriology, 2 per horse.Does not differentiate EHV-1 from EHV-4Dr. Dale Godson
306-966-7316 (main office)
Prairie Diagnostic Services,
52 Campus Dr
Saskatoon, SK   S7N 5B4
then click "Forms"
8:00 - 5:00
MBNasal or conjunctival swab*, lung, spinal cord, spinal fluid. Test will differentiate EHV-1 from 4; sequencing needed to know if EHV-1 is nEHV-1. Cost $32.00; TAT 1-2 days.Does not differentiate EHV-1 from EHV-4Dr. Tomy Joseph
Veterinary Diagnostic Services
545 University Cr
Winnipeg, MB   R3T 5S6
www.gov.mb.ca/agriculture/livestock/pubs/equine_submission.pdf 8:30 - 5:00

  • In a live horse, test and sample of choice is PCR on a nasal swab or buffy coat sample (20 ml EDTA blood).
  • *For nasal swabs, Starplex Multitrans® Collection and Transport System swabs work well. Can also use a plastic handled untreated absorbent cotton swab broken off and put in a tube with 1/2 ml phosphate buffered saline or saline. Swab nasal mucosa very vigorously to get cells, not just nasal mucous and debris. Do not use bacteriological swabs with charcoal or gel-type preservatives. Do not use wooden handled swabs.
  • Swabs (Starplex Multitrans) available from WDDC Cat. No. 115798 in a 5 pack for $12.90.
  • Ship all samples chilled on ice packs for overnight arrival. In general, do not ship for arrival on holidays or weekends.
  • Questions, please contact Dr. Simon Otto 780-427-8228 or Dr. Jagdish Patel 780-644-5093

1 http://www.aphis.usda.gov/animal_health/emergingissues/downloads/ehv1final.pdf

2 Patel J. Disease Impact: Equine Herpesvirus Myeloencephalopathy. Animal Health Forum, Alberta Agriculture and Rural Development, Food Safety Division, Vol. 13(1): 5 - 6; February 2008.

3 http://www.avma.ab.ca/
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This document is maintained by Amrit Matharu.
This information published to the web on August 14, 2009.
Last Reviewed/Revised on September 23, 2014.