Evaluation of the safety of vaccinating mares against equine viral arteritis during mid or late gestation or during the immediate postpartum period

Abstract

When faced with a substantial risk of natural exposure to EAV, it would appear to be safe to vaccinate healthy pregnant mares up to 3 months before foaling and during the immediate postpartum period. Vaccinating mares during the last 2 months of gestation was associated with a risk of abortion; this risk must be weighed against the much greater risk of widespread abortions in unprotected populations of pregnant mares naturally infected with EAV.

Further evaluation and validation of a commercially available competitive ELISA (cELISA) for the detection of antibodies specific to equine arteritis virus (EAV)

“…A total of 3255 archived serum samples were evaluated for the presence of EAV antibodies by the cELISA and VNT. This panel included archived sequential serum samples (n=1361) collected from 146 horses that were either experimentally infected with various field or laboratory strains of EAV (n=number of horses; virulent Bucyrus strain [VBS; ATCC‐VR796]; American Type Culture Collection [ATCC], Manassas, Virginia, USA]: n=1; KY84: n=28; CA95G: n=6; recombinant virulent Bucyrus strain [rVBS]: n=12; recombinant EAV 030H [r030H]: n=2; rVBS/HK116S : n=4 and rVBS/VaccNS4m : n=4) or vaccinated with the current modified live virus (MLV) vaccine strain (ARVAC; Zoetis, Florham Park, New Jersey, USA) : n=83 or recombinant MLV vaccine strain (rMLVB); n=6 (MacLachlan and others 1996, Balasuriya and others 1999, Patton and others 1999, Balasuriya and others 2002, Balasuriya and others 2007, Go and others 2008, Zhang and others 2008, Broaddus and others 2011, Summers‐Lawyer and others 2011, Go and others 2012, Zhang and others 2012, Campos and others 2014). With the exception of two studies, the serum samples were collected at 0, 2, 4, 6, 8, 10, 12 and 14 days post‐experimental infection or vaccination and thereafter weekly up to six weeks (42 days post challenge) depending on the study.…”

“…With the exception of two studies, the serum samples were collected at 0, 2, 4, 6, 8, 10, 12 and 14 days post‐experimental infection or vaccination and thereafter weekly up to six weeks (42 days post challenge) depending on the study. In one study, serum samples from MLV vaccinated mares and their foals were collected at 0, 12 and 48 hours post parturition up to 60 days post vaccination (Broaddus and others 2011). In another study, serum samples from horses experimentally infected with EAV CA95 were collected up to 1.5 years post inoculation (Patton and others 1999).…”

Equine viral arteritis: A respiratory and reproductive disease of significant economic importance to the equine industry

“…Vaccination of pregnant mares with the MLV vaccine is not recommended, particularly during the last 2 months of gestation due to the high risk of abortion (Broaddus et al . ). Similarly, it is not recommended to vaccinate foals aged <6 weeks or dams with foals aged <6 weeks.…”

Host Factors that Contribute to Equine Arteritis Virus Persistence in the Stallion: an Update

“…The virus can also be transmitted to naïve recipient mares via embryo transfer from a donor mare inseminated with EAV-infective semen [28]. Movement of carrier stallions, contaminated frozen or chilled semen, and contaminated embryos have increased the spread of the virus nationally and internationally [28][29][30]. Carrier stallions solely constitute the natural reservoir of the virus, and thus, play a central and critical role in the epidemiology of EVA.…”