Equine Viral Arteritis (EVA) with respect to stallions from which semen is collected and transported from the premises in the fresh cooled or frozen state:

1. Breeding stallions unvaccinated for EVA should be tested for evidence of equine viral arteritis infection using the serum neutralization test. No stallion should be vaccinated for the first time without its pre-vaccination titer first being established.

2. Seronegative stallions (titers of less than 1:4) should be vaccinated at least 28 days prior to breeding or semen collection and receive an annual booster. Vaccinated stallions should be isolated for 28 days post vaccination. Seronegative stallions that are vaccinated for EVA should be vaccinated at least 28 days prior to breeding or semen collection and receive an annual booster. Vaccinated stallions should be isolated 28 days post vaccination.

3. Seropositive stallion’s (unvaccinated) shedding status should be determined every 12 months either by: Attempted virus isolation on semen or, test breeding to at least two seronegative mares and monitoring for seroconversion at 14 and 28 days post breeding.

4. Seropositive stallions (vaccinated) need not be tested for virus shedding if seronegative prior to initial vaccination.

5. The serologic and shedding status of non-EVA vaccinated seropositive stallions should be made known to mare owners receiving the semen. This information should also be reported to state authorities where so required and to breed associations where so required.

6. Stallions seropositive for EVA from natural exposure need not be vaccinated.
Guidelines pertaining to mares which will be inseminated with transported fresh cooled or frozen semen.

1. Seronegative mares to be inseminated with semen from an equine arteritis virus shedding stallion should be vaccinated against EVA at least 21 days prior to insemination. These vaccinated animals should be isolated for 21 days post vaccination.

2. Mares seropositive for EVA from natural exposure need not be vaccinated.

Reviewed by AAEP board of directors in 2010.

Resource Type

  • Position Statements


  • Equine Viral Arteritis (EVA)
  • Infectious Diseases
  • Reproduction

Publish Date

January 1, 2010