# strangles testing and results



## horselover88 (17 June 2014)

Quick question as new area to me.

Horse on yard had strangles test in order to be moved to new yard. showed antibodies, so second test was done and these are still showing. Vet has suggested guttural pouch test, just to confirm whether move is ok or if infection is present. Advised seperating horse etc while awaiting results.

However, horse has not been off yard in two years, have had no new arrivals to yard and horse has shown no symptoms what so ever (has been at least 2 weeks since first test). So I have a few questions:

What is likelyhood of horse having strangles?
What is incubation period?
How much is guttural pouch test and how accurate are the blood tests?
How long for infection to clear, if present?
Could antibodies still be present from previous infection before new owner as horse came from competition background?

Thanks in advance!


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## Switchthehorse (17 June 2014)

Hi 

I am no vet so this isn't accurate but my horse had high levels when she had a test a few years ago and she had high readings, and then high readings again 2 weeks later, my vet (mr doom and gloom) told me she was a carrier, she would have to live a separate life forever, never mix with other horses and would probably end up being pts.

I asked another vet for a second opinion who said yes the test results were high, but if she was going to have strangles symptoms would show in the next couple of weeks, so we left her 2 more weeks, no symptoms and so she was allowed to move to the new yard - general consensus was she had been exposed to it at some point recently but not contracted it, or that her readings will always be high.

Three years later i move yards again and expected high readings but they were low (hooray)

I believe the guttural pouch isn't cheap - think £400 - £600 but worth it for a definitive answer.. having said that is it really definitive? My instinct would be leave it for a couple of weeks and see if any signs of infection and if not test again.. i definitely think antibodies could still be present but they will decrease over time

But like i say none of this is qualified, just experience   Good luck!


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## Lippyx (17 June 2014)

He could be a carrier, which I believe means he will test positive, but not show any symptoms. He could still pass it on to other horses.
A friend of mine went through the same problem. Antibodies showed up, yet horse showed no symptoms at all. Went through treatment, which was long and expensive, and afterwards tested negative. Even when he had the Guttural pouch done, there was hardly any "gunk" in there. I still think it was a virus, rather than full blown Strangles.

The problem is, its only the antibodies that "suggest" strangles, there is no real blood test for strangles it self.


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## horselover88 (17 June 2014)

Thanks for the response.

Just seems funny that horse has not been off yard, yard has never had outbreak or issues, we have no new horses and horse has absolutely no symptoms. 

Can horses test positive twice in blood tests, and then show negative for guttural pouch test? What is the likelyhood of this?


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## horselover88 (17 June 2014)

Lippyx said:



			He could be a carrier, which I believe means he will test positive, but not show any symptoms. He could still pass it on to other horses.
A friend of mine went through the same problem. Antibodies showed up, yet horse showed no symptoms at all. Went through treatment, which was long and expensive, and afterwards tested negative. Even when he had the Guttural pouch done, there was hardly any "gunk" in there. I still think it was a virus, rather than full blown Strangles.

The problem is, its only the antibodies that "suggest" strangles, there is no real blood test for strangles it self.
		
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If horse has no symptoms etc, but tests positive in guttural pouch test, will that then mean they cannot move? How accurate the these tests?


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## mjcssjw2 (17 June 2014)

good grief is it common to be asked for a strangles test when moving yards? I have never heard of this before


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## MontyandZoom (17 June 2014)

The antibodies detected are specific to strangles so the positive test means that the horse has either been exposed to strangles in the not so distant past, has a current infection or has a latent infection (ie is a carrier and could pass it on to other horses). 

If it is the former, waiting a bit longer may mean a repeat blood test would show declining antibodies and you would be ok to move. However scoping and flushing of the guttural pouches would be the preferred option. Depending on cost you could treat at the same time as taking the guttural pouch swab if there is a chance he is a carrier as the treatment is usually placing penicillin into the guttural pouches to kill any nasties that might be living in there. 

You would be talking a few hundred pounds though so not ideal!


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## peaceandquiet1 (17 June 2014)

Our vets did a talk on strangles and said one in ten horses will remain a carrier with dried up pus-like deposits ? chondroids in the guttural pouches, which will be detected by scoping and treated by flushing and antibiotics I think. Frankly I feel, having a bill for about £250 for strangles blood tests, that the whole think has turned into a bit of a racket........


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## Lippyx (17 June 2014)

horselover88 said:



			If horse has no symptoms etc, but tests positive in guttural pouch test, will that then mean they cannot move? How accurate the these tests?
		
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There is no test for Strangles, its all if certain levels are high, then is "could" be strangles. That's what I have learnt from my friends experience. Horse couldn't move until levels dropped below 0.2... His was 4.0!!!!! Hence them thinking he was a carrier!


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## w1bbler (17 June 2014)

Had a horse years ago with strangles. Vet said they will still blood test positive up to 6 months later & needed gutteral pouch to prove clear so he could be turned out again.
He also said that a horse will testpositive after exposure to the bug even if they don't develop the disease.


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## burtie (17 June 2014)

In the New Forest area strangles is endemic in the semi feral ponies and although 'touch wood' we've not had an outbreak for the last couple of years it is not uncommon for foals sold at auction to develop strangles when they move off to their new homes. I have been told by a couple of local vets that most horses kept in the New Forest would test positive to the anti-bodies even if they have never had the virus although I've personally never put this to the test!


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## horselover88 (18 June 2014)

So from what I read, sometimes the tests can be inaccurate? Surely if most horses become immune after infection, then it seems silly to treat with vaccinations/antibiotics which are not even 100% promised to work?

Horse in question has not been away from yard for ages, and no new arrivals, but had two high results and so guttural pouch has to be done. What do the results from this show?

Also, how likely are horses to be carriers, and how are these treated? Treatment sounds expensive for what cannot be garaunteed success!


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## horselover88 (18 June 2014)

Can't edit my post, but following on, vet saw no signs of chrondoids and everything was clear- no pus, nothing.


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## JanetGeorge (18 June 2014)

Years ago, I bought a horse who had been to Liverpool and had his immune system kicked out - to cure BAD sarcoids.  (It worked.)  He returned to his livery yard - where we also had a horse - and I bought almost right away.  Both horses came home and the horse with no immunity arrived weith early signs of Strangles.

Only two other horses got it at the livery yard - two Irish horses - who arrived about the same time as 'my' horse came back from Liverpool - but they got it a week later.

Livery yard owner did the calculations and 5 horses were identified as possible carriers - and were isolated and tested.  The oe that turned out to be a carrier had been on the yard for 2 years - and they'd not had a Strangles case since his arrival.  All the horses there had obviously developed some immunity.  Obviously he needed a wash-out etc.

I had assued that the horse who travelled home with him would get it - so they were isolated together.  He never showed a sign.


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## horselover88 (18 June 2014)

Just an update:

Horse had two positive readings
Guttural pouch done and swab taken- swab has come back negative. Awaiting results of Guttural Pouch wash.
Horse has no symptoms (and has not had any in the past either) and first blood test was done over 3 weeks ago. 

What is likelyhood of guttural pouches also being negative? If they came back positive, how would you treat/manage this, given that horse has no symptoms and does not have active infection?


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## Asha (18 June 2014)

horselover88 said:



			Just an update:

Horse had two positive readings
Guttural pouch done and swab taken- swab has come back negative. Awaiting results of Guttural Pouch wash.
Horse has no symptoms (and has not had any in the past either) and first blood test was done over 3 weeks ago. 

What is likelyhood of guttural pouches also being negative? If they came back positive, how would you treat/manage this, given that horse has no symptoms and does not have active infection?
		
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It's quite possible the test could come back negative . Mine did. I'd owned my mare for Around 8 years at the time, and had never shown any symptoms etc. never been on a yard with strangles in that time. In fact been on our private yard for 5 years. She was tested for strangles as the stud I was going to use insists on it. Couldn't believe it when the results came back positive. I totally panicked, anyway my vets did a guttural pouch, and results came back negative. What I didn't realize is the blood tests they use aren't always accurate and can throw false positive results.


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## peaceandquiet1 (18 June 2014)

The horses who is a carrier may show no symtoms but may shed the bacteria periodically if under the weather or stressed etc., thus becoming infectious again.


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## Fides (18 June 2014)

Asha said:



			It's quite possible the test could come back negative . Mine did. I'd owned my mare for Around 8 years at the time, and had never shown any symptoms etc. never been on a yard with strangles in that time. In fact been on our private yard for 5 years. She was tested for strangles as the stud I was going to use insists on it. Couldn't believe it when the results came back positive. I totally panicked, anyway my vets did a guttural pouch, and results came back negative. What I didn't realize is the blood tests they use aren't always accurate and can throw false positive results.
		
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They aren't actually false positive results - they just show that the horse has had strangles at some point, not necessarily a current infection. Guttural pouch washes are the only definitive diagnosis.

Incidentally you can get false negatives with a a horse that has it but has only recently been infected.


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## Asha (18 June 2014)

Fides said:



			They aren't actually false positive results - they just show that the horse has had strangles at some point, not necessarily a current infection. Guttural pouch washes are the only definitive diagnosis.

Incidentally you can get false negatives with a a horse that has it but has only recently been infected.
		
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According to my vet, it was a false positive.


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## Exploding Chestnuts (18 June 2014)

horsemadmum1 said:



			Our vets did a talk on strangles and said one in ten horses will remain a carrier with dried up pus-like deposits ? chondroids in the guttural pouches, which will be detected by scoping and treated by flushing and antibiotics I think. Frankly I feel, having a bill for about £250 for strangles blood tests, that the whole think has turned into a bit of a racket........
		
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We had a mass outbreak [don't pretend there is no problem then turn  infected horses out into the herd ] and the testing was free at the time, of course that is not free as in there will be no charge from the vet. The yard now asks for incoming horses to have a blood test and be in isolation ........... talk about closing the stable door............
There are quite a few empty stables now.


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## Fides (18 June 2014)

Fides said:



			They aren't actually false positive results - they just show that the horse has had strangles at some point, not necessarily a current infection. Guttural pouch washes are the only definitive diagnosis.

Incidentally you can get false negatives with a a horse that has it but has only recently been infected.
		
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Asha said:



			According to my vet, it was a false positive.
		
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They're making it 'simple' for you to understand. What they probably mean is that the horse has had a positive test, indicating it has been infected at some point (and now has immunity) but the horse does not exhibit any sign of a current, active infection. 

The test is polyclonal antibodies and is highly specific. It is sensitive, but only if titres are over a certain level - hence false negatives. It's not like a pregnancy test where a tumour can give a positive result - that would be a false positive.


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## DW Team (18 June 2014)

I have just bought a new mare and my yard asked me to have a strangles test done.  She was tested on the Monday results negative came in on the Friday Mare arrived on Saturday.


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## horselover88 (18 June 2014)

Thanks for all the responses.

So if the horse has no sign of anything in guttural pouches, no old chondroids, looks very healthy, and swab results come back negative, how likely is horse still likely to come back positive for guttural tests? 

I think I have just about got my head around the ins and outs of each type of test. Essentially guttural pouch is clearest answer, blood tests and swabs can throw up anomolies or incorrect results etc. 

what is treatment for a carrier who has no chrondoids/pouches are extremely clear and healthy, is negative for swabs but positive for pouch test? Are they likely to actually be a risky carrier? Especially as horse has shown absolutely so signs or symptoms in the several years it has been at yard. 

Vet has been great in explaining to all liveries but would be good to understand from another owners perspective!!


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## Exploding Chestnuts (18 June 2014)

burtie said:



			In the New Forest area strangles is endemic in the semi feral ponies and although 'touch wood' we've not had an outbreak for the last couple of years it is not uncommon for foals sold at auction to develop strangles when they move off to their new homes. I have been told by a couple of local vets that most horses kept in the New Forest would test positive to the anti-bodies even if they have never had the virus although I've personally never put this to the test!
		
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Streptococcus Equi 
https://microbewiki.kenyon.edu/index.php/Streptococcus_equi
is a bacterium not a virus, so quite a bit bigger, and different characteristics......... viruses are so small they can attach to dust and be carried in the air, strangles is contagious ... spread by touch [ and snot/sneeze].
When the local yard blood tested the ponies used in the RS 50% showed antibodies, indicating that the disease rumbled around at low intensity. The ponies were not in contact with the main yard which had active strangles.


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## Asha (18 June 2014)

Fides said:



			They're making it 'simple' for you to understand. What they probably mean is that the horse has had a positive test, indicating it has been infected at some point (and now has immunity) but the horse does not exhibit any sign of a current, active infection. 

The test is polyclonal antibodies and is highly specific. It is sensitive, but only if titres are over a certain level - hence false negatives. It's not like a pregnancy test where a tumour can give a positive result - that would be a false positive.
		
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Genuine question here - are you a vet ?

My situation was mare dropped off at new equine clinic, vet aware of the blood test. Mare had not been off private yard, and neither had the others for sometime. No new horses. Got a call from the stud informing me of the results, can't remember the figure but it was high enough for the vet to have a melt down, as if accurate she would have had strangles and showing real clinical symptoms. Which she didn't, healthy looking horse. Vet performed Guttural pouch immediately, results came  back clear. Had all my other horses tested, all clear.  Therefore original test was false positive, - or in other words wrong !


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## Radar Lugs (18 June 2014)

Last year I was moving yards and had both my horses tested. My older horse came back clean but my then 4 year old came back with a weak positive. I had been on the yard for 2years and the youngster hadn't been off the yard in that time. No other horses on the yard had any symptoms and few had been off the yard.
Guttural pouch test came back completely clean. Very annoying.
Was told by my vet that the tests were supposedly 95% accurate but they were getting a lot higher "false" result rates.
Cost me £80 per horse for the initial swabs and another £240 for the guttural pouch test. £400 just to move yards and be told my horses were clear!


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## Fides (18 June 2014)

Asha said:



			Genuine question here - are you a vet ?My situation was mare dropped off at new equine clinic, vet aware of the blood test. Mare had not been off private yard, and neither had the others for sometime. No new horses. Got a call from the stud informing me of the results, can't remember the figure but it was high enough for the vet to have a melt down, as if accurate she would have had strangles and showing real clinical symptoms. Which she didn't, healthy looking horse. Vet performed Guttural pouch immediately, results came  back clear. Had all my other horses tested, all clear.  Therefore original test was false positive, - or in other words wrong !
		
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No I'm not a vet but a biomedical scientist and do these types of tests for a living. I currently work doing human tests but have worked in an animal lab in the past. If your horse had high levels on the test and no current infection it indicates a strong immune system. When immunising you want high titres on antibody to the disease as it indicates better protection, this similarly... Vets quite often 'dumb it down' for the general population and term it false positive. It is false in that there is no current infection only, not that the test is wrong-hence needing guttural pouches doing.The initial test cannot tell if the horse has an active infection and it is misleading of them to imply this


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## jojo5 (18 June 2014)

My boy and I have jst been through all of ths prior to moving to a new yard. In te first round of blood tests his results were 0.2 and0.3 - I was told that the 0.3 result was on the borderline and we therefore had to wait two weeks and test again.  I have owned the horse for 17 years and known him for longer, and we have never encountered a horse with outward signs of strangles.  (I do realise that the infection may not be fully apparent in a horse.)  Anyway, cue much panic in case a) he has strangles - ovbiously more terrifying or b) I lose the place on the new yard. Two weeks later his results are 0.1 and 0.1!  With call-out each test cost me over £100.   I have not been able to understand how his titre could fall so much. I do realise I have been lucky in that I did not have to ave the pouch wash, but it all seems rather random.


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## Fides (18 June 2014)

jojo5 said:



			My boy and I have jst been through all of ths prior to moving to a new yard. In te first round of blood tests his results were 0.2 and0.3 - I was told that the 0.3 result was on the borderline and we therefore had to wait two weeks and test again.  I have owned the horse for 17 years and known him for longer, and we have never encountered a horse with outward signs of strangles.  (I do realise that the infection may not be fully apparent in a horse.)  Anyway, cue much panic in case a) he has strangles - ovbiously more terrifying or b) I lose the place on the new yard. Two weeks later his results are 0.1 and 0.1!  With call-out each test cost me over £100.   I have not been able to understand how his titre could fall so much. I do realise I have been lucky in that I did not have to ave the pouch wash, but it all seems rather random.
		
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A level of 0.3 to 0.1 is negligible... It is low enough to be test variance. Anything less than 200 that is stable or declining is considered non-infective (by eliza method).


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## jojo5 (19 June 2014)

Fides said:



			A level of 0.3 to 0.1 is negligible... It is low enough to be test variance. Anything less than 200 that is stable or declining is considered non-infective (by eliza method).
		
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Hi Fides, - I wish Liphook had agreed with you that 0.3 was in the negligible range - would have saved me loads of anxiety and £100!  I was told 0.3 was the start of the range which needed to be re-tested, though I notice someone else on here was told 0.4?  Not sure what you mean re the '200' - how does this relate to 0.2 etc?  I do see what you mean by 'test variance' but this variance cost me a lot of heartache and money.


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## Fides (19 June 2014)

jojo5 said:



			Hi Fides, - I wish Liphook had agreed with you that 0.3 was in the negligible range - would have saved me loads of anxiety and £100!  I was told 0.3 was the start of the range which needed to be re-tested, though I notice someone else on here was told 0.4?  Not sure what you mean re the '200' - how does this relate to 0.2 etc?  I do see what you mean by 'test variance' but this variance cost me a lot of heartache and money.
		
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Its frustrating isn't it? The difference between 0.2 and 200 is just as it sounds - a lot  a titre of 2 means if you dilute it with an equal volume of diluent you still get a result, 4 - 4 times, 8 - 8 times. You get the picture... Yours is so low to be negligible  this is assuming the did an ELISA test though.


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## horselover88 (19 June 2014)

My horse showed results of 0.2 and 0.3 on first test for routine check to get out and about- If I had known these were negligible I may have not bothered with all the extra costs! I guess there is always the risk of carrier status still though? 

Does the risk of spreading infection depend on symptoms, as well as guttural pouch results etc? What about in a horse that shows no signs, has no symptoms, has not for 5 years and had positive blood test, but negative swab?


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## jojo5 (19 June 2014)

So, is there a vet HHO who can explain why some of us are asked to re test with what seems like a negligible reading?  Not only does this mean extra cost, but an awful lot of stress for the owner, plus possibly difficult situations for some people if in between results become known before they are confirmed as negative -and do all labs request re-tests at the same level of initial result?  Any vets out there could see from this thread that there is an awful lot of confusion for owners in this.  Of course responsible owners will want test to be certain, but first of all we need general clarity about what is needed.  ('...Climbs off soap box....')


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## Fides (19 June 2014)

Negligible is ELISA is the method used - less than 200 is considered low with ELISA which is the most sensitive method. OP didn't actually state which test used.


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## horselover88 (19 June 2014)

Fides said:



			Negligible is ELISA is the method used - less than 200 is considered low with ELISA which is the most sensitive method. OP didn't actually state which test used.
		
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Is this the same as the blood test which measures antibody levels? If so, then yes the ELISA test was the one which was used. Excuse my ignorance- I am new to the whole strangles testing, although very aware of the nasty thing itself.


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## jojo5 (19 June 2014)

Fides said:



			Negligible is ELISA is the method used - less than 200 is considered low with ELISA which is the most sensitive method. OP didn't actually state which test used.
		
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Personally, I wasnt informed exactly which test would be used - just told that results of 0.2 and 0.3 meant another test was required.  I do feel like taking this up with Liphook....


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## horselover88 (19 June 2014)

I change my mind. My brain hurts!


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## horselover88 (20 June 2014)

Just a quick thought (possibly silly one!), but could flu vaccinations affect antibody levels? 

Horse had first test and then flu jab. This blood test showed results of 0.3 and 0.2 so second blood test done again and results slightly higher- although nasal swab etc were negative. I am probably way off, but I just thought if they use a weakened strain of the flu virus to boost immunity, could this impact on other antibodies, especially those which are similar?


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