Okay, so I have some interest in breeding to Florencio this year, and he is unfortunately EVA possitive. Does anyone have experience with vaccinating and isolating mares for EVA? I always thought it was a month of quarantine, but a vet told me last week that it is two weeks. Is that correct? Also, how far away from other horses does the vaccinated mare need to be? What are the risks of having a pregnant (unvaccinated) mare on the same property with one quarantined for EVA? Do handlers have to disinfect all tools, rakes, equipment, plus their hands and boots before approaching non-vaccinated horses?
The quarantine period is 21 days following vaccination. It is also recommended to quarantine for a similar period after you have bred to a postitive shedder stallion. "Quarantine" means keeping the animal away from other susceptible animals in the farm - in other words, stallions, pregnant mares, and horses that will be coming in contact with those two groups. It is OK to keep the mare in contact with other mares and geldings as long as they are not pregnant or coming in contact with pregnant mares or stallions. The quarantine needs to be non-contact - in other words no risk of the interested animals coming onto physical contact with each other. The virus is not particularly durable outside the animal.
The risks to other animals on the farm are low. Transmission following immunization has not been recorded with this vaccination, but because it is a modified live virus vaccine, it does theoretically exist. Following breeding, although the mare herself is protected having been vaccinated previously, there is still the possibility of the virus being shed as excess semen is expelled, or the outside possibility that the vaccination did not have enough of an effect and she is suffering from a sub-clinical case.
Vaccination for EVA is not a particularly difficult arrangement to achieve, and it is our opinion, that it would be advantageous if all mares were vaccinated, as the disease is seen in other sectors of the horse breeding industry, is little understood or known about, and has the potential to be devastating in the event that there is an outbreak.
Hello, and thanks for the info! If I understand correctly, quarantine vaccinated mares for 21 days AND quarantine for 21 more days following insemination with a EVA positive stallion?
"The virus is not particularly durable outside the animal." Could a dog lick the nose of a vaccinated and quarantined mare, then lick the nose of a non-quarantined horse a few minutes later and transfer EVA to unvaccinated horses? Kind of a silly sounding question, but it's animal-to-animal-to-animal.
What is the earliest age in which I could vaccinated young mares that may be bred to EVA positive stallions at some point in their lifetime? I have two 2 yr old fillies that could get vaccinated with the two mares, if it makes sense to do so at this stage in their lives.
quarantine vaccinated mares for 21 days AND quarantine for 21 more days following insemination with a EVA positive stallion?
Could a dog lick the nose of a vaccinated and quarantined mare, then lick the nose of a non-quarantined horse a few minutes later and transfer EVA to unvaccinated horses?
I suppose so, but the chances of it happening would be pretty remote, but "never say never"!!!
What is the earliest age in which I could vaccinated young mares
One recommended protocol is to vaccinate all young stock at about or just prior to 270 days of age. Boostering annually will be required, but by vaccinating that early one is providing maximum protection.
There are some other issues relative to vaccination of colts, wherein one has to make sure that one is not limiting the countries to which one plans to export the animal or semen from him if vaccinated, but the restricitive countries are minimal, and you are still providing the best protection by doing that vaccination - just check first.
In an effort to understand EVA better, I have a few more slightly unusual questions. If a person vaccinated their young fillies prior to being of breeding age and the fillies were required to get yearly vaccinations, do the fillies need to be quarantined each time they are vaccinated? What would happen if a person (future owners, for example) failed to keep up their yearly vaccination, and at some point wanted to revaccinated? Would the then mares need to go through the quarantine process again? If an unvaccinated stallion live-covered a EVA vaccinated mare (which I assume would test possitive for EVA, once she has the antibodies???), would the unvaccinated stallion then become EVA positive? I would have to imagine he would, since isn't EVA a sexually transmitted disease? Thanks for your expertise on these matters.
do the fillies need to be quarantined each time they are vaccinated?
It would not be necessary to do so.
...revaccinated? Would the then mares need to go through the quarantine process again?
That would be recommended.
unvaccinated stallion live-covered a EVA vaccinated mare... would the unvaccinated stallion then become EVA positive?
No! The mare does not shed the virus like the stallion may. The only time a mare or gelding will routinely shed the virus is when they are in the active stages of the disease. Having antibodies to the disease and being infectious are not the same - if you are innoculated against 'flu and sneeze on someone, they will not become infected with 'flu! Same for EVA vaccines.
It is a sexually transmitted disease, from the stallion to the mare - the stallion can become a permanent shedded of the virus, which is harboured in his secondary sex glands as long as he is a stallion (it is testosterone-dependent for survival in-vivo). If the stallion is gelded, he will no longer shed the virus, which is why neither mares nor geldings will shed once they are ouside the active stages of the disease.
Could you expand on this? I am not sure I understand completely. Is the vaccine that is used live? Therefore, when mares are vaccinated, EVA is in their bodies in an active stage, and they are shedding until the virus dies and the horse has created antibodies???? Although, that is not to say that a horse that is innoculated with the EVA vaccine HAS the full blown virus, right? It is just that the virus is active, contageous, and the horse is shedding during the quarantine period? Is this why they are quarantined so long? OR, I am completely missing the boat on all of this? Is it true that once a horse is vaccinated for EVA, if it's blood was tested for EVA, the horse would test positive?
Can you fully describe the course of the disease and how it effects a horse when it is infectious? What are the symptoms? I understand that EVA can cause unvaccinated mares to lose their fetuses. Are their other dangers?
By "active" I mean that the animal is actually actively infected with the disease - to use my 'flu analogy from above further, if you have the 'flu, while you are coughing, sneezing and running a fever, you are in the "active" stages of the infection and will be shedding the causative pathogen yourself to all around you. Once you are through that stage, you will carry antibodies to the disease, but will not be shedding the pathogen. If someone else that has the 'flu sneezes on you - as long as the strain is the same - you will not become reinfected as you have the requisite antibodies to protect you.
The vaccination that is used for EVA consists of a modified live virus. Consequently, although it has never been seen to be the case, theoretically the mare could become actively infected and shed the virus following administration - again, it has never been seen to happen, but is a theoretical possibility, hence the 3 week quarantine.
Once immunized against EVA, a blood test will be likely to show not the virus itself, but antibodies against the virus. Note that the titre level will drop if not reimmunised, but if a mare was exposed to an active infection of the virus (i.e. "caught" EVA from another animal) the antibody levels will persist higher, longer.
EVA is primarily a respiratory disease, so it may manifest the same symptoms as an equine 'flu, and also may produce distal limb edema, and also edema of the mammary glands in mares and the sheath in stallions/geldings. In the pregnant mare, abortion is likely within 3 weeks of infection. In the stallion there is a high possibility of the pathogen being harboured in the secondary sex glands and being secreted upon ejaculation (a "shedder" stallion) on a permanent basis.
The big problem is that the disease may also be asymptomatic - in other words, the fully infected animals show absolutely no symptoms, so one does not know if an animal has been exposed, or is even actively infectious, simply by looking at it.
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