Video on Lyme Disease in Horses

SARAH: Caitlin unfortunately had a horse who is diagnosed with Lyme disease this past winter. She lives in Connecticut. As a New Yorker, I can sympathize.

DR LYDIA GRAY: It is not the state.

SARAH: I've been there. Her horse's most prominent symptom was behavioral change. And she said she went from a laid back, easy horse to being very difficult to handle. And she's wondering what are some of the other signs and symptoms of Lyme disease in horses. What are the treatment options? Can it cause any long term complications?

DR LYDIA GRAY: OK. As far as signs, this is a tough, tough one to diagnose because the signs can be all over the place. And behavior is one of them, but it's probably not the one that veternarians or owners think of as first. This is notorious for shifting lameness, in that one day the right front hurts, and then a couple days later the left front hurts, and then it goes around. Low grade fever, muscle soreness-- we're hitting that again-- and also something called hyperaesthesia, which means if I touch you, it hurts more than it should. You're extra sensitive to just touching.

They can have neurological problems. Ataxia-- like weakness and wobbling. Head tilt. What else? Oh, uveitis, so eye infection. So, see, it's almost everything. But really we think of swollen joints and arthritis and lameness, that kind of thing. Shifting lameness.

SARAH: As far as treatment options and long term complications, what would you say?

DR LYDIA GRAY: Treatment, oh boy, this is tough, too, because it looks like the tetracycline family is the most effective. It's a bacteria. It's a spirochete. So oxytetracycline intravenous, which may mean either you have to bring the horse to the vet or the vet has to come to you. And it's a long time. It's like a month. So it's expensive, also.

SARAH: Is it like one shot or are you hanging an IV bag and fluids and all that?

DR LYDIA GRAY: Yeah. It's like every day. And so there's doxycycline, which is sort of the next generation, and that's oral. It's not very bioavailable, and you still have to give it for weeks and weeks and weeks. They're looking at a new, I guess it would be third generation of tetracycline called minocycline. And that might work better. It's more expensive right now. But this is an active area of research.

And she had complications. The thing with Lyme disease is-- as we know in people-- you might not be able to completely clear the infection. And you're left with some not residual deficits as much as just lingering problems. Like maybe-- not for sure in this horse, but here's an example-- maybe the behavior doesn't completely go back to what it was. The other problem is when you're in an area that has a high incidence of Lyme disease or your horse or you have had it, you're kind of always thinking-- because the range of signs is so big-- that maybe anything my horse does is Lyme disease.

And it doesn't have to be. Maybe your horse is really lame. So this is probably not what she means, but it's a complication. Just not thinking of other things that your horse could really have. It's a problem.

SARAH: Right. Changing the way you evaluate your horse.

DR LYDIA GRAY: Yeah. So don't neglect a true diagnosis for anything that's wrong with your horse. I mean, don't assume that a fever is Lyme disease. It could be something else. So always have everything checked out by a vet.

SARAH: You used a word in your answer about the treatment that I think not a lot of people understand but we come across a lot at SmartPak. I mean, you used a lot of tetracycline and all of those things. But the one that I'm thinking of is 'bioavailable.' Can you explain what that means for horses?

DR LYDIA GRAY: So biologically available-- and we speak of in terms of an oral-- so when you swallow something, how much of a pill or a powder or whatever that you are taking in eventually gets into the bloodstream and around the body. And so some things are really bioavailable, and some things are not. And some things you have to combine. A perfect example in people-- if you take like an iron supplement, you have to take something with it that has vitamin C like orange juice that helps it get absorbed better.

So some things you don't have an absolute bioavailability, but you can affect it with other things simultaneously.