Equine Herpesvirus-1 Myeloencephalopathy

Admissions protocol for suspected EHV-1 cases

• Questions may be directed to EFAVC Director, NC State Veterinary Hospital (VH) 919-513-6615

• All cases presenting with or having history of fever &/or signs of respiratory disease & acute ataxia must be housed in isolation until test results are available to rule out EHV-1. If any concern at all for EHV-1 upon admission, the case will be worked up and housed in an Isolation stall until consultation with the Equine Medicine service occurs. Final decisions on housing and management will be made by the Equine Medicine faculty on clinics.
• Upon taking a call for a neurologic horse, the receiving clinician will ask the owner/agent or RDVM the following questions:
  • What is the temperature of the patient or has it been taken?
  • History of travel in the last 30 days?
  • History of respiratory disease in patient or other equids on the farm? (cough/nasal discharge)
  • History of fever & neurologic dysfunction in other equids on the farm?
  • History of Abortion?
• Horses with high fevers and signs of neurological deficits will be tested for EHV-1 by PCR diagnostics via nasopharyngeal swab as well as by whole blood. Detection of a positive PCR for EHV-1 in such instances should warrant isolation and limited movement of exposed horses.

Management of suspected EHV-1 Cases

• Effort should be made to house EHV-1 suspect cases in ISO 5. When efficiently possible, effort should be made to provide additional separation between EHV-1 suspect case(s) and other cases in isolation.
• EHV-1 suspect cases will be managed through the following protocols:
  • High Differential: Cases presenting with recent history of travel, history of respiratory disease on the farm, fever, and neurological deficits. These cases should be housed in Isolation until consultation with the Equine Medicine service.
    • Operations Management: Observe personnel management protocols as written in “Management of Individual Confirmed EHV-1 Cases” until EHV-1 test results are negative and/or quarantine protocol is complete for confirmed positive cases.
  • Low Differential: Cases where EHV-1 is considered unlikely due to the history but is still possible. Housing and management decisions will be made through consultation with the senior Equine Medicine faculty on clinics at the time.
    • Operations Management: Observe standard Isolation protocols. Effort should be made to minimize interaction with the patient until test results are available.

Management of Individual confirmed EHV-1 Cases

• When a confirmed EHV-1 positive case is identified, the Equine Medicine faculty on clinics, Equine Service Chief, and EFAVC Director (“Committee of Three”) will meet to determine and communicate a plan for hospital operations and quarantine.
• Once a confirmed case is housed in Isolation, a one stall separation buffer must be made to provide separation between EHV-1 case and other cases unless otherwise directed by Committee of Three.
• Operations Management: Horse will be housed in Isolation for the entire duration of its stay and effort will be made to limit patient contact as much as possible while still providing appropriate care.
  • Only disposable PPE will be utilized: Tyvek suit, plastic boot covers, double gloves, hairnet, and face shields.
  • When personnel have had contact with the patient, they may not enter the EFAVC again until they have showered. The MRI entrance can be utilized to access showers in the Health & Wellness Center restrooms.
  • One technician/assistant will be designated to treatment of the patient to minimize personnel contact unless otherwise directed by the committee of three. Once showered, this person is expected to re-enter the EFAVC and continue assisting with inpatient treatments.
  • The stall will only be picked once a day at the end of an Animal Attendant’s shift as assigned by the EFAVC Attendant Supervisor unless otherwise directed by the committee of three. Attendants will not re-enter the EFAVC and will go home immediately after contact with the patient.
  • Any breach of protocol shall be reported immediately to the Committee of Three for further management.
• Horses with prior confirmed EHV-1 positive results presenting to the EFAVC during the quarantine period (28 days post last clinical sign) shall be managed following the aforementioned protocol.

Management of Multiple Cases or Intrahospital Transmission

• As much as possible operations should adhere to the Management of Individual confirmed EHV-1 cases section.
• Order of stalls to occupy: ISO 5, ISO 4, ISO 3, ISO 2, ISO 1
• If there are more than five cases needing Isolation or known exposure occurs in the general hospital area and all five ISO stalls are occupied with EHV-1 cases, the hospital will begin quarantine efforts to consist of:
  • The committee of three will make all operational decisions with consult and approval from Hospital Administrator and Associate Dean & Director of Veterinary Medical Services.

Diagnostic tests and sample submission

• Initial testing for EHV-1 will be collected with a naso-pharyngeal swab and resulted through the point-of-care PCR analyzer. The protocol for utilizing the analyzer and recording results is posted adjacent to the analyzer. Results will be entered into the electronic medical record by MMD lab staff on the next business day.
  • If the PCR is negative, EHV-1 is considered to be ruled out.
  • If the PCR is positive, secondary samples must be submitted to the MMD lab for repeat testing. The patient will be managed using protocols as written in “Management of Individual Confirmed EHV-1 Cases”.
• When repeat testing is required following positive point-of-care results, positive results will be confirmed by MMD lab staff via in-house PCR analyzers on the next business day. A separate clinical request will be needed in the electronic medical record for this additional testing. 
  • Samples can be placed in the brown refrigerator across from Cytology outside of business hours (M-F 8a-5p), or handed directly to MMD lab staff during business hours.