Strangles test to move yards positive, am completely thrown.

[HighlandCowbag]

Am in the process of moving yards. Have to have clear strangles tests. 2 ponies, 1 8 year old owned since 2 year old 1 14 year old owned since 4 year old but was bred by my yard owner and always been on current yard.

14 year old pony came back positive, 8 year old negative, they in together. Never had strangles on the yard, no new liveries in 5 years, not competed in 5 years, only vet and farrier on and off.

Only bug we've had was strepzoo about 7 years ago, only a yearling ever affected. My pony never had so much as a stable cough. It's utterly thrown me, vet coming next week to do gutteral pouch swabs.

Does anyone have any experience of anything like this? How common are false positives? I'd immediately assume he is a carrier but we have never knowingly had strangles. Yard is just me and my mate with the odd livery over the years but nothing new on for 5 years. We've had a mix of old and youngstock so would assume at least 1 would have shown symptoms. Am shocked and devastated tbh.

Had a pony come back positive with no knowledge of him ever having had it. Think vet said they can be carriers without symptoms. He had to have another test to show the antibody levels hadn't increased, proving he didn't have a current infection. Then he was allowed on new yard.

Yes vet is coming back next week and doing a wash/scope on his gutteral pouches to investigate further. After frantically googling it seems you can get false positives, not just that it's an old infection still having an antibody response but actual false positives.

It's such a pain in the arse. Really need to get them moved for various reasons and am away next week so wanted them settled before I went. Doesn't look like it's happening tho. Fuck sake.

It’s really not a very good test, you get loads of false positives. My mare had a low positive when I bought her, and I was gutted and nearly backed out of the purchase.
When they repeated the test after 4 weeks, they re-tested the original sample as well and both were negative!
The way the test is done, the difference between negative and positive is minuscule.
My vet said that yard owners insist on the test because it’s there, and everyone is terrified of strangles, but whether it’s actually a useful test is very doubtful.
Good luck!

Yes you can get false positives and it is much more likely than him being a carrier. Good luck op

Thanks both. Vet came to scope yesterday and I quizzed him hard re the blood test.

Apparently it doesn't differentiate between strepzoo and strepequi (strangles). We know we had strepzoo 8 years ago so assume that the test was a positive for strep, but obviously we don't know which strep until the scope results are back.

His gutteral pouches were clear, no sign of current strangles or being a carrier so that's positive. Will get 2 results back, 2 days apart as they need to test, then grow cultures. If the first comes back positive, it's again just positive for strep, its the culture one that is important.

It's a very invasive procedure though, and I wouldn't want to have to repeat it. I can't see that this test is going to make much difference to strangles rates. Tho vet did say more and more he is scoping full yards to identify and treat carrier ponies. I just wish it was possible to differentiate between the 2 strep bacteria to avoid scoping ponies that probably don't have strangles.

That is really interesting OP. Manyyears ago we had 2 incidents 6 months apart when we suspected strangles. Each time 2 ponies were tested. Each time 1 tested positive for strangles and the other positive for strep zoo. These were different ponies kept in different locations in closed herds. My Vet said he had never come across it before

I suspect that the blood tests are a relatively new thing, I was expecting nasal swabs. And it's probably one of those tests that will develop with time to avoid the gutteral pouch tests in ponies testing strep positive and further investigation will only be needed with actual strangles positive cases.

Will update with the results when I get them.

I suspect in your case, if you had 2 closed herds you had 1 carrier at least. The one testing positive for strangles probably wasn't the carrier. The one testing positive for strepzoo possibly had strangles immunity and also had been exposed to strepzoo previously. And the immune response to the strangles kicked off the less serious strepzoo. They can both apparently live harmlessly in the gutteral pouches until triggered by an immine response incident.

Results back, both negative as I thought.

Yay, that's great news OP! I'm glad you can get on and get them moved!
I was talking about this to a friend today, and said it's becoming really quite limiting, as it's become difficult to e.g. take your horse on holiday, or send them for a few weeks professional schooling, as you have to have strangles tests either end. It wouldn't grate so much if it wasn't such an inaccurate test!

Exactly, it will really curtail movement. I wouldn't mind if it was an actual strangles test but it's not, it's an immune response to strep test.

Hope I like the new yard after all this. Been on old yard 15 years so it's a massive change. And going from full assisted to DIY. It's going to be a massive change but hopefully one for the better.