Tuesday, March 1, 2011

Taking Precautions

This morning the vet came to give five of the horses - Pie, Dawn, Sugar, Scout and Misty - their intranasal strangles vaccine.  The other three horses - Fred, Fritz and Charisma - use two different vets, and I believe they will also come shortly to do the strangles vaccinations.  We usually do our first round of spring vaccinations (5-way: Eastern and Western encephalitis, tetanus and flu/rhino; and West Nile booster) towards the end of March, followed a bit later by the rabies and strangles vaccinations.

We've moved up our timing on the strangles vaccinations because we're taking some extra precautions due to Drifter's expected arrival in the second half of March.  It turns out he may very well have had a relatively mild case of strangles about nine months ago.  He lives in a small herd totaling three horses, and last May a mule was added to the herd.  The mule was apparently somewhat of a rescue and came in with a bit of a snotty nose.  After that, two of the three horses, including Drifter, developed what was quite likely strangles.  Neither horse was terribly sick - they'd all been vaccinated - but that's what the vet thought it was although no culture was done to confirm it.  Drifter did have a small abscess in his throat that burst.  Both horses made a good recovery - they had a complete course of penicillin and were closely monitored - and neither has shown any sign of illness since.  Drifter seemed very healthy to me when I saw him last fall, and my vet will check him over very carefully during the prepurchase exam.

I've learned a lot about strangles and its transmission over the last several weeks.  Here's some good information and here's some more information. The last time I'd seen a horse who became sick with it was around 1970 when I was a teen and my horse Snow developed a full-blown case - this was in the days before vaccines - including the very enlarged abscessing glands that are typical of the disease.  Strangles is a form of strep that is specific to horses, and it is very contagious although not all that persistent in the environment.  The likeliest means of transmission is nose-to-nose contact and contamination of shared water tanks.  Most horses, even those who get full-blown cases, recover well.  The disease can be a threat to very young horses and horses with compromised immune systems, and there are occasional serious complications.

The introduction of vaccines, first an intramuscular one (with some risk of abscesses at the injection site) and then the intranasal one, is a very good thing, although I have learned that the vaccines have relatively poor efficacy and may not prevent infection in all cases.  Vaccination does, however, reduce the risk of infection and also will likely reduce the severity of symptoms in a horse that does become infected, so it is advisable.  Our vet recommended that Pie be revaccinated even though he was vaccinated for strangles  about five months ago.

Most horses, once fully recovered, no longer can transmit the disease.  Horses should be considered still potentially contagious for 6 to 8 weeks after they are fully recovered.  And a very small percentage of horses may become silent carriers of the disease, although most of these do show some symptoms - typically infectious nasal discharge.

I've also learned that most vets recommend that a horse who has had strangles should not be vaccinated for at least a year after having strangles - there's a very nasty complication that can arise, called purpurea hemorrhagica, which is an antibody/antigen auto-immune reaction leading to generalized swelling of the blood vessels - it's extremely painful and can cause serious damage to the horse.  This complication can arise for other reasons too, but vaccination after a horse has had strangles is one cause.  A significant percentage of horses with strangles will have life-long immunity to it, but many do not.  A blood titer to determine antibody levels should be done before vaccinating a horse who has had strangles.

Both Drifter's owner and I have talked to our vets and I have also spoken to the University of Wisconsin veterinary clinic.  Due to his treatment with a full course of penicillin and apparent full recovery and good health (to be confirmed by my vet at the prepurchase), the likelihood that he is a carrier is very low.  There are tests to determine carrier status - involved repeated deep intranasal swabs under sedation - but these tests are more reliable in detecting carriers immediately after infection and also fail to detect carriers in a number of cases, so we have decided not to do them.

The recommendations we received were to isolate Drifter in a separate paddock for three weeks after his arrival and to revaccinate all our horses at least three weeks before he is directly introduced to them.  If he were a carrier, the stress of the long trailer ride and the move to a new barn would likely provoke new symptoms - fever and/or a snotty nose.  Then it would be possible to culture any nasal discharge, and treat him with antibiotics if needed.  In fact, we really should have been isolating any new arrival to our barn for two to three weeks anyway and have never done so.  Although we've never had problems in the past, this is a practice we should probably use in the future.  While he's in isolation, I'll still be able to work with and ride him, just not in close proximity to other horses, and we'll take appropriate precautions  like keeping his equipment and supplies separate and avoiding cross-contamination.

All these precautions are probably unnecessary, but worth taking in our opinion.

* * * * * *
On another equine health note, our main veterinary practice is holding a client education seminar tonight on worming practices - and they'll be providing free fecal testing of one horse for each person who attends (and bringing a sample qualifies you for door prizes!).  Apparently over 100 people have signed up - there's so much interest there's actually a waiting list - it's very good that they're doing this and the degree of interest in the local horse community is great.  I'll let everyone know what they have to say.

24 comments:

  1. Good post. We'll get our horses vaccinated in April and strangles is one on the vaccines.

    Hope things work out well.

    Dan

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  2. Thanks for the info, I know next to nothing about strangles.

    I'm also interested in the worming seminar. With all the recent studies saying we need to change our worming habits I'm a little lost as to what exactly I should be doing.

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  3. Very good information! I had a whole farm outbreak about a year and a half ago--it was awful. I didn't lose anyone, but it was so bad that everyone actually went through two rounds of swollen glands. It was a particularly nasty strain. Poor Fabian even had a node burst on the SIDE of his head.

    My horses got it from a horse that I took care of for a friend. She was a silent carrier--not a single symptom at all. Lucky me....

    Fabian's glands under his jaw are permenantly scarred from it--they are enlarged, but not filled. They don't hurt him at all to poke around, and when you press on them they deflate--they're just all stretched out, and you can see them from the side. People who don't know what he went through might suspect he's currently sick, but he's not at all. It's just a weird scar from how badly it had hit him.

    Good thinking to take precautions--I hope I never have to go through anything like that again.

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  4. I wish someone in our area would do a seminar like that, they'd get great attendance for it here, too, I'm sure. Thanks for the information about strangles, it probably is better to be overly cautious. I've seen two horses with it at my last barn, but it was a big barn with lots of people in and out for the clinics, rodeos and gaming they hosted there. We've always vaccinated for it, and so far so good.

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  5. The last barn I was at did the isolation thing, but still had a strangles outbreak. I heard even birds can be part of the transmission stream?

    I would like to switch to fecal testing. I'll have to suggest a similar approach to our vet.

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  6. Great post about Strangles. I didn't know that about the abscess possibility in the throat. How painful that must be! :(

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  7. Whooooeee! 100 people with samples? That's a whole lot of poop!

    Our vet held something similar a couple years ago, too. He had other equine practitioners there, too, like a farrier, dentist, chiropractor/acupuncturist, and quite a few companies that provided free samples and products to try. It was lots of fun, I met some new people and learned some useful information about equine care, too.

    Hope you have a great time, too :)

    ~Lisa

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  8. I'm sure Drifter is fine but it's always a good idea to isolate a new arrival for a while. We always have. Good informative post, thanks.

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  9. The strangles vaccine scares me, especially the nasal one. You should have the new horse swabbed to make sure he's not a shedder... if he's negative, there's no risk of him contaminating your herd.

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  10. Dom - as I understand it from our vets, this long after infection and recovery, a simple nasal swab won't tell you anything unless the horse is actively sick. Shedders who are not chronically ill/snotty typically only shed under stress. Also, the deep nasal swab technique may not produce good results either as the deep nasal/throat area and gutteral pouches are likely to have been recolonized by a variety of bacteria in the absence of an active strangles infection. Deep nasal swabs are more useful immediately after infection - that's why we elected not to do them.

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  11. Kate--I'm commenting on your previous post--I have to admit, you made me smile. Glad to know that neither one of us will tolerate being nipped at. But overall your Pie has been a real champ. To have ridden the way you have over the winter (infrequently and in tough conditions) on such a young horse is really proof that he's a good one. Cheers--Laura

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  12. Isolating Drifter sounds like a good strategy and you're taking all the precautions. You should be fine :)

    Strangles scares me... questionable efficacy of vaccines and isn't there something called "bastard strangles" where the infection occurs in other parts of the body?

    I don't allow nose to nose or any sharing of hoses etc. at my place since my boarder has an incomplete medical history and goes off property to large shows.

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  13. I wish my barn practiced the solitary confinement for new incomers. May have saved us from Strangles out break last summer.

    Bonnie never showed any symptoms but Rosie had green snot nose for a day, nothing beyond that, but we still treated with antibiotics to be on the safe side.

    Better safe then sorry is what I say.

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  14. Very informative post. My horse was in a barn with a strangles outbreak years ago. He was vaccinated with the muscular injection and got so sore in his neck he could hardly walk.

    I'll be getting spring shots soon and now we use the nasal vaccine. My vet is really clever about giving it as the horses really don't seem to like it much. The vet usually uses a kind of "sneak attack" to administer it. *L*

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  15. Good post - you have some great information.
    The day I bought my horses, as I was on my way home and they were due to arrive in 3 hours, I found out that a neighbor had brought her 3 horses, all with strangles, back to her pasture from a boarding barn. One of the horses had abscesses, the others hadn't gotten them...yet, but were sick. Talk about setting me and my other neighbors in a panic! She finally listened to a friend and returned her horses to the boarding facility where they would receive medical care and not possibly infect another area of the county.
    Despite the fact that they were only on her property for 2 or 3 hours we all took precautions. Our horses were vaccinated and we used a ton of fly spray as that would be the only vector of infection since our horses would not have contact with anything on her property.

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  16. The problem with strangles is you can do everything right (quarantine, etc) and still end up with strangles going through your barn. You never know what will (or won't) trigger a carrier to start shedding. I think you are taking good precautions though.

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  17. Great info on Strangles... I learn so much here. I am doing the fecal testing, for worms, for the first time tomorrow. I just realized that I wouldn't give myself random and unnecessary toxins unless ABSOLUTELY essential. So why have I been doing that to my horses?

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  18. I've been doing fecal counts lately and have found no need to worm. My horses don't go anywhere around other horses and the climate here is very dry- not conducive to worm reproduction cycles.

    Good post on strangles. Spring shots are coming up soon.

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  19. Melissa - you're right - no matter what you do, including isolation of new horses, there can be strangles - but reducing the odds is the best we can do.

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  20. Dreaming - good point about transmission by flies - if they land on the nose/ruptured abscess of a horse who's got it and then land on another horse, that can be a vector for transmission.

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  21. Calm, Forward, Straight - as I understand it, what's called "bastard strangles" is when the infection moves to lymph glands elsewhere in the body. One of the vets I spoke to said that this could be due to improper use of antibiotics, where they were given only so long as clinical symptoms were present, rather than a longer course of treatment, allowing the infection to persist and spread through the body. This vet said that correct use of penicillin has reduced the incidence of bastard strangles, although horses with weakened immune systems - very young horses, very old or debilitated horses or those with Cushings - could still be subject to complications like this.

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  22. Strangles is one of those super scary things the way it can just blow through a herd in nothing flat.
    I have to say I got the giggles over the seminar blurb at the bottom. Looks like it pays to be a party pooper for once - door prizes and everything ;o)

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  23. Our horses got the IM strangles injection last spring. It was their first time getting a strangles vaccine of any sort. Our Paint gelding went lame on all 4 legs and was very lethargic for 3 days after vaccinations, he subsequently recovered completely. Our (new) vet strongly believes it was the strangles vaccine that led to that. He said that because of many reactions to the IM vaccine, they never use it and only do it intranasally. I admit I'm wary of having them vaccinated again this spring.

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  24. Thanks for the info! I didn't know all that.

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