Strangles blood test

now_loves_mares

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I've owned my horse (gelding) for about 16 months now. He's kept at home with my other horse (mare) Neither have left the yard for 7 months as I'm pregnant. Both are in rude health.

The gelding came from Ireland and past history not known, he was just 5 when I got him. The mare I've owned since she was 8 months old. The gelding was due to go on loan, and his livery yard asked for a strangles blood test, as a friend had recently moved her retired mare to mine to keep my mare company when the gelding left. The blood test was done on the 3rd week of her arrival, and we received the result exactly 3 weeks after she arrived. No-one has been sick, I've known this mare for 6 years or so, I know she hasn't had strangles in that time, and 99.9% sure the yard she came from hasn't had any issues either.

However, my gelding came back with a "low positive" on his bloods. One was a 0.2 and one was a 0.4. The yard then refused to take him unless I had a negative swab. I decided as I was already this far into pregnancy not to faff around with this (can't currently drive lorry for a start), and he's just stayed at home. Another 3 weeks have passed, safe to say nobody has strangles.

Questions are, therefore:

- What is the most likely cause of the positive test? Things I read suggested "exposure within the last 6 months" but he's not been anywhere, and as the mare that arrived hasn't brought strangles with her (has been here 6 weeks now) it appears she isn't the source. He could have been exposed to it in Ireland, but like I said that was 16 months ago, so I would have thought would be gone by now.

- can you get false positives on the bloods? Does it show other virus' (and again, no sign of that in any of the 3 of them)

- is there no point in the 3 week incubation any more? As the new mare had already been at mine for 3 weeks without showing any symptoms, should the yard still have insisted on the test (obviously it is their choice, but I mean from a risk perspective).

- once I'm back on board, what would I have to do to clear my conscience. As the horses are at home and therefore incredibly low risk, if nobody shows any signs of illness, could I in good faith start competing again in a few months despite this positive blood test?

Bit confused, and there is always so much hysteria around strangles I want to make sure I'm clear in what could have happened, what might happen, and what if anything I need to do to keep my own and everybody else's horses safe.
 
They will show a reaction on bloods if they have had or come into contact with it in their lifetime- natural immunity and all that.

Especially from Ireland not overly surprising.

It nothing to worry about, but if you are you could swab
 
If you think any horses will move on or off yard you do need to swab because it is possible that the horse could be carrying the infection. You can find an information sheet from AHT here http://www.aht.org.uk/skins/Default/pdfs/F245.pdf Obviously if he is not a carrier then no problem - but if he is you would need to either treat him or permanently isolate him.
 
Hate the blood tests for yard moves. It takes 2 weeks after exposure for the test to show positive so new yards can think horse is clear when it isn't. Can show positive yonks after infection is gone so can create unnecessary panic. Basically a single test tells you zip really. You need 2 tests at least 2 weeks apart before you can even start to draw any draw any useful conclusions. The chances are that one of your horses picked up the infection within the last 12 months & like a lot of cases was asymptomatic so you never realised - that's why it spreads so well. I would have a second blood test done (& blood test the other too). I would expect that the titres will fall/remain stable at a low level. In that case you are just dealing with post infection traces. If titres rise or the other horses level are high- talk to your vet. When my horses had strangles 1 had about a thumbnail sized blob of snot only when ridden & a slight cough for a week, the other had no symptoms at all. Neither even had a raised temp. If the first horse hadn't recently come from a dealer we would probably not have called the vet. As it was by the time we got the swab results the symptoms had passed. It would have been so easy not to realise what they had.
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I had my 2 tested a few years ago for a yard move and 1 came back with a weak positive. I had had him for nearly 2.5 years by then, he was never off the yard as wasn't backed (was only 4 at the time) and hardly any other horse on the yard was out competing.
Not wanting to wait 2 weeks I had him guttural pouch tested, which, surprise surprise, came back completely clear.
I called his breeder, who I bought him from, and as far as she knew, he had never been in contact with strangles.
Vet then tells me that the tests aren't as accurate as stated and they had had a fair number of false positives. In the mean time I was over £300 out of pocket to get a clear result. Needless to say I wasn't impressed :-(
 
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