Question About EVA Vaccine, Again !

[Elfe]

Two mares, A and B. In spring 2012 both were vaccinated. Mare B got pregnant and should foal mid May. Mare A did not get pregnant. Mare A and B share a paddock and shed. I plan on breeding mare A this spring. Can I give her an EVA booster and leave her in the same paddock/shed with mare B ?

Mare C is a maiden and lives with a younger filly and a gelding in a paddock/shed adjacent to where mare A and B live, separated by an eight foot
aisle. I plan on breeding mare C this spring. Can I vaccinate her and leave her where she is ?
None of the stallions these mares are being bred to are EVA positive, as far as I know.
Thanks !

[Equine_Reproduction]

@Elfe;6831456

Two mares, A and B. In spring 2012 both were vaccinated. Mare B got pregnant and should foal mid May. Mare A did not get pregnant. Mare A and B share a paddock and shed. I plan on breeding mare A this spring. Can I give her an EVA booster and leave her in the same paddock/shed with mare B ?

Yes. You can leave her in there if you are simply boosting the vaccination. If you plan on breeding her, you must (or you “should”) move her out of that pen during the time you inseminate if you are breeding to an EVA positive stallion

Mare C is a maiden and lives with a younger filly and a gelding in a paddock/shed adjacent to where mare A and B live, separated by an eight foot
aisle. I plan on breeding mare C this spring. Can I vaccinate her and leave her where she is ?

Yes, but why not vaccinate the younger filly at the same time? It would be relatively easy and since you are doing both and they are in with a gelding, now would be the time when “I” would do it. It also makes future boostering easier.

Good luck!

[Elfe]

[QUOTE=Equine Reproduction;6831961]
Yes. You can leave her in there if you are simply boosting the vaccination. If you plan on breeding her, you must (or you “should”) move her out of that pen during the time you inseminate if you are breeding to an EVA positive stallion

Yes, but why not vaccinate the younger filly at the same time? It would be relatively easy and since you are doing both and they are in with a gelding, now would be the time when “I” would do it. It also makes future boostering easier.

Good luck![/QUOTE]

Thanks !
Explain, please, why I should vaccinate the younger filly. I am not planning on breeding her anytime soon, is there another reason ?
Thanks again !

[Equine_Reproduction]

[QUOTE=Elfe;6832321]
Thanks !
Explain, please, why I should vaccinate the younger filly. I am not planning on breeding her anytime soon, is there another reason ?
Thanks again ![/QUOTE]

Because you would have to isolate her away from the others for the initial vaccination. On boosters, they don’t need to be isolated. So, it would be easier to do it now and then not have to worry about keeping her away from others later when you vaccinate.

[Elfe]

[QUOTE=Equine Reproduction;6832439]
Because you would have to isolate her away from the others for the initial vaccination. On boosters, they don’t need to be isolated. So, it would be easier to do it now and then not have to worry about keeping her away from others later when you vaccinate.[/QUOTE]

That makes sense, thank you !
Would I have to boost every year or only the year she gets bred ?
Also, is it necessary to draw blood before vaccinating to show the mare is negative ? Is that ever an issue, for instance in the case of export ?

[rodawn]

Well, if you have her close to mares you are breeding or in the same pasture with mares you are breeding, then you should do annual boosters to all your girls, young and old, prior to any breeding taking place. Annual vaccination boosters are done, (and this applies to any vaccine), because the immune system needs constant reminding so-to-speak.

Once you have vaccinated, pulling blood will show antibodies, meaning she has successfully developed antibodies to the disease the vaccine was protecting her against. If you’re exporting, you would show the vaccinations records of the horse.

As Kathy mentioned - the very first vaccination you have to isolate her - separate paddock (no ability for nose touching over the fence!), separate water source - especially away from your pregnant mares as this vaccine is a modified live virus. Pregnant mares should never be exposed to any live vaccine and kept away from horses exposed to any live virus vaccines. But once you get to the annual booster stage, nobody has to be isolated.

Kathy is so modest, but there is an EXCELLENT article on Kathy and Jos’ website
that I’ve linked to here.
http://www.equine-reproduction.com/articles/EVA.shtml

[Elfe]

[QUOTE=rodawn;6833543]

As Kathy mentioned - the very first vaccination you have to isolate her - separate paddock (no ability for nose touching over the fence!), separate water source - especially away from your pregnant mares as this vaccine is a modified live virus. Pregnant mares should never be exposed to any live vaccine and kept away from horses exposed to any live virus vaccines. But once you get to the annual booster stage, nobody has to be isolated.

http://www.equine-reproduction.com/articles/EVA.shtml[/QUOTE]

This is the part I really don’t understand: since the pregnant mares have been vaccinated and therefore have immunity, why would you have to isolate them from recently vaccinated other horses ?
IOW’s if the vaccine is effective they have immunity, if the vaccine is not effective then why bother ?
What am I missing ?
Thanks !

[rodawn]

The article explains most of it.

[QUOTE=rodawn;6833543]

As Kathy mentioned - the very first vaccination you have to isolate her - separate paddock (no ability for nose touching over the fence!), separate water source - especially away from your pregnant mares as this vaccine is a modified live virus. Pregnant mares should never be exposed to any live vaccine and kept away from horses exposed to any live virus vaccines. But once you get to the annual booster stage, nobody has to be isolated.[/QUOTE]

The sentence following my bolded part, my apologies. I MUST clarify. It should read: In a general non-pregnant herd, once you do annual boosters, nobody needs to be isolated. In the regular nonpregnant herd that you are choosing to vaccinate for the very first time, they can all be done in one herd.

However, you should still remove your pregnant mares from those who are being vaccinated - for the protection of the unborn foals. To not do so is to risk her aborting the foal.

[QUOTE=Elfe;6833981]This is the part I really don’t understand: since the pregnant mares have been vaccinated and therefore have immunity, why would you have to isolate them from recently vaccinated other horses ?
IOW’s if the vaccine is effective they have immunity, if the vaccine is not effective then why bother ?
What am I missing ?
Thanks ![/QUOTE]

It’s not the mare. It’s her unborn foal you need to protect.

Pregnant mares and thus their unborn fetuses should never be exposed to a live vaccine, any live virus vaccine, let alone the EVA live vaccine, or exposed to a horse who has been given a live virus vaccine. Even if it’s a booster, remove the preggos from the herd you are boostering.

This is not the same as a KILLED VIRUS vaccine which are safer for the unborn fetus. We give various vaccinations to pregnant mares that are all killed virus. Pneumabort-K or Prodigy being one of them.

The EVA vaccine is a modified live virus, and this virus is lethal to unborn foals and will result in abortion within 30 days of exposure. It is also not safe for newborn foals to be exposed (direct nose to nose contact with its mother or herd companion), so if you are planning to vaccinate a mare who has a foal at side, ask your vet about when is a safe age of the foal to be at so you can vaccinate the mare.

[Elfe]

[QUOTE=rodawn;6834087]
The article explains most of it.

The sentence following my bolded part, my apologies. I MUST clarify. It should read: In a general non-pregnant herd, once you do annual boosters, nobody needs to be isolated. In the regular nonpregnant herd that you are choosing to vaccinate for the very first time, they can all be done in one herd.

However, you should still remove your pregnant mares from those who are being vaccinated - for the protection of the unborn foals. To not do so is to risk her aborting the foal.

It’s not the mare. It’s her unborn foal you need to protect.

Pregnant mares and thus their unborn fetuses should never be exposed to a live vaccine, any live virus vaccine, let alone the EVA live vaccine, or exposed to a horse who has been given a live virus vaccine. Even if it’s a booster, remove the preggos from the herd you are boostering.

This is not the same as a KILLED VIRUS vaccine which are safer for the unborn fetus. We give various vaccinations to pregnant mares that are all killed virus. Pneumabort-K or Prodigy being one of them.

The EVA vaccine is a modified live virus, and this virus is lethal to unborn foals and will result in abortion within 30 days of exposure. It is also not safe for newborn foals to be exposed (direct nose to nose contact with its mother or herd companion), so if you are planning to vaccinate a mare who has a foal at side, ask your vet about when is a safe age of the foal to be at so you can vaccinate the mare.[/QUOTE]

O.K. So what you are saying is that the vaccine does not protect the mare from aborting if exposed to the virus ?
That is the main reason for me to vaccinate in the first place !
Thanks for the clarification.

[Jos]

[QUOTE=rodawn;6834087]

The EVA vaccine is a modified live virus, and this virus is lethal to unborn foals and will result in abortion within 30 days of exposure.[/QUOTE]

This is incorrect.

In fact, in the face of an outbreak of EVA and the risk of pregnant mares being exposed to the virus, vaccination is recommended. It is correct to say that routine vaccination of pregnant mares with Arvac (the MLV EAV vaccine) is not recommended, but research has indicated that it’s use does not cause abortion at all stages of pregnancy:

Broaddus CC, Balasuriya UB, White JL, Timoney PJ, Funk RA, Holyoak GR. (2011) Evaluation of the safety of vaccinating mares against equine viral arteritis during mid or late gestation or during the immediate postpartum period: J Am Vet Med Assoc. 2011 Mar 15;238(6):741-50

[rodawn]

Hi Jos,
What you say contradicts several of our local vets then? They don’t want pregnant mares vaccinated with the live vaccine, or for that matter, any live virus vaccine.

Can you clarify why this modified live vaccine is okay to give pregnant mares, when the vets here, including repro vets, really shy away from it?

I suppose if push comes to shove and there is some wild outbreak, then the vaccine is the lesser of the two evils, but that would only be in the case of an outbreak, at least according to these vets.

[Jos]

[QUOTE=rodawn;6834594]
Can you clarify why this modified live vaccine is okay to give pregnant mares, when the vets here, including repro vets, really shy away from it?[/QUOTE]

Unfortunately not. All I can offer is the peer-reviewed research and the personal knowledge of individuals that have used the vaccine in pregnant mares without negative effect. Perhaps ask your veterinarians for their research sources and compare the two and go from there! I do have tremendous confidence in Dr. Peter Timoney however, who is the acknowledged world-expert on EVA, and co-author Dr. Holyoak runs a close second!

[rodawn]

Thank you, Jos!

[Elfe]

Jos:
Please clarify:

1. Does vaccine protect pregnant mares from aborting if exposed to virus, be it in the respiratory or semen form ?
2. If yes, then no need to isolate vaccinated mares from first time vaccinated horses?
3. If mare has been vaccinated, then newborn should have acquired immunity through colostrum and there should be no problem boosting/vaccinating mare a few days after foaling ?

Thank you !

[ahf]

[QUOTE=Elfe;6834843]
Jos:
Please clarify:

1. Does vaccine protect pregnant mares from aborting if exposed to virus, be it in the respiratory or semen form ?
2. If yes, then no need to isolate vaccinated mares from first time vaccinated horses?
3. If mare has been vaccinated, then newborn should have acquired immunity through colostrum and there should be no problem boosting/vaccinating mare a few days after foaling ?

Thank you ![/QUOTE]

Here is Dr. Timoney’s faculty page at Gluck:
http://www.ca.uky.edu/gluck/TimoneyPJ.asp

I have found him to be incredibly gracious and helpful when I’ve emailed him with questions regarding EVA.

[Jos]

The answers to some of these questions are actually contained within the abstract to which I linked.

@Elfe;6834843

1. Does vaccine protect pregnant mares from aborting if exposed to virus, be it in the respiratory or semen form?

The virus is the virus. It’s not a different form for the reproductive version of the disease vs. the respiratory. Hence a mare that is protected by vaccination is protected regardless of source of exposure.

2. If yes, then no need to isolate vaccinated mares from first time vaccinated horses?

The reason one isolates following vaccination is to avoid unidentified seroconversion of non-vaccinated horses should they come into contact with the newly vaccinated animal. If seroconversion occurred, it could produce an inexplicably seropositive animal if that contact animal were subsequently tested. Consequently as there is no concern of seroconversion of an already-vaccinated (and therefore seroconverted) horse, there is no need to isolate vaccinated animals.

3. If mare has been vaccinated, then newborn should have acquired immunity through colostrum and there should be no problem boosting/vaccinating mare a few days after foaling ?

This is largely explained in the linked abstract: All postparturient vaccinates were seronegative at foaling; all of them seroconverted after vaccination. No adverse effects were detected in any of their foals.

People that have questions about EVA, please review the articles on our site that cover pretty much all of the basic questions and a few of the more advanced ones! There are several different articles on EVA to be found in the articles section.

[Elfe]

Thanks !