SNAP test vs Cornell Multiplex test for Lyme diagnosis

[Bogie]

Last fall I had more horse evaluated for an intermittent lameness issue plus some behavioral issues. He was sound a the walk and trot, would canter fine on the right lead but refused to hold the left lead canter for more than a few steps. As part of the evaluation we pulled blood for Lyme. I was told he was negative and subsequently had his SI joints injected in November (symptoms were consistent and he’d had a slip out hunting which could have aggravated it) and mesotherapy. His back was definitely less sore after the treatment, but he was never willing to pick up or hold the left lead canter.

Didn’t do much over the winter except hack him at the walk and trot. Lots of hill work, ground poles, etc. when the weather and footing allowed. He has gotten progressively crankier and very sensitive to touch. He’s never much liked to be groomed but now is even more reactive. He did have a couple of massages and although it was hard to work on him, he loosened up and moved better after them. I also worked with my farrier to give him a bit more support behind as the vet thought it might have been contributing to his soreness.

Today I had another vet from the practice out for a lameness exam. We are having wind gusts of 36 mph and could only ride outside so vet gave him a small amount of dorm so I could ride him safely. Horse was sound both directions at walk/trot/canter, although as recently as Monday would not canter to the left. Dorm has some pain relieving qualities as well as muscle relaxing and anti-anxiety properties, which certainly helped, but I was interested that he is sound except for a sore back.

Vet told me that when the titres were run last year he was actually positive on the SNAP test and negative on the Cornell Multiplex. We drew blood again and started him on Doxy for a two week test to see if his behavior improves.

So, has anyone else come up with a false positive using the Cornell test? I thought that it was supposed to be more accurate. Certainly living in New England, Lyme is a very big possibility. I feel terrible that he might have suffered with it all winter!

[emeraldcity]

The snap test is a test of exposure, not active infection. I’m not specifically familiar with the Cornell test, but I’m guessing it’s a titer? So the snap test is just telling you that he has been exposed at some time in the past, but doesn’t necessarily indicate an active infection. I was told by my vet that the snap is actually designed for canine blood, and said she doesn’t use it at all for horses.

Tests for tick disease also typically are testing for antibodies, so it’s possible that an animal can show symptoms before enough antibodies build up to test, so you could have just tested too early to get a positive.

[Bogie]

Interesting idea. Certainly in New England every horse has been exposed to Lyme. I’m surprised they don’t all have it all the time. My dogs each had it several times and Doxy made a huge difference almost immediately. This horse has lived int New England for the past 12 years. I’ve treated him once for Lyme and have regularly tested for it.

I just hope it makes a difference. Of course, since Doxy is an anti-inflammatory, it could simply make him feel better because of that. If only they could speak.

[Posting_Trot]

My previous horse had lyme disease three times, so I really hate it.

My understanding is that the Cornell test is more accurate. But, it’s possible that at the time that the blood was pulled, the disease had not progressed enough for the horse to have produced significant antibodies to the disease. Anyway, here is the Cornell lab’s description of the test: https://ahdc.vet.cornell.edu/docs/Lyme_Disease_Multiplex_Testing_for_Horses.pdf
Good luck. It’s a terrible disease.

[bt1]

Agree with all the above, but also want to suggest checking his Vit E level.

[Bogie]

@bt

Agree with all the above, but also want to suggest checking his Vit E level.

Yes, he is deficient in Vitamin E. I supplement him with that and also magnesium.

[Bogie]

Update: After four days of Doxy, my horse is almost back to normal. Back is no longer sore, he’s picking up the left lead willingly and consistently, his crankiness level is way down. Haven’t gotten the new titers back, but am very optimistic that he’s on the road to recovery.

[walktrot]

My gelding had Lyme a number of years ago and he turned right around several days after starting doxy. He was on it for 6 weeks, though, and I think I’m very comfortable with that since he has had no problems since. I know a lot of people do treat for a shorter period, but I think it’s worth an extra couple of weeks to increase the probability you’ve killed all the nasty organisms.

[Bogie]

@walktrot

My gelding had Lyme a number of years ago and he turned right around several days after starting doxy. He was on it for 6 weeks, though, and I think I’m very comfortable with that since he has had no problems since. I know a lot of people do treat for a shorter period, but I think it’s worth an extra couple of weeks to increase the probability you’ve killed all the nasty organisms.

I agree. My vet is talking about 6-8 weeks.

[jawa]

Doxy has anti-inflammatory properties, so he could be feeling better from that or because it is acting on the Lyme.

[Bogie]

@jawa

Doxy has anti-inflammatory properties, so he could be feeling better from that or because it is acting on the Lyme.

I know. That’s the tricky part. However, I did try giving him bute for several days, which made no difference. So I think it’s not just the anti-inflammatory properties. I am still waiting for the second titer results.