I am hoping someone can help me with some information on chronic Lyme Disease. My horse has been off with an unexplained lameness since last May. It showed up initially as slight “hitchiness” in her right hind leg. She was 10 years old at the time so I thought she might be starting to get a bit arthritic and I scheduled to have her hocks injected. When the vets from our local college came out to do the injections, she was showing lameness in her right foot. They X-rayed, didn’t find anything so suggested it was likely a soft tissue injury and to give her 8 weeks off. She was still not right after the time off so followed with various blocks, injections, X-rays and finally a bone scan. Lyme Disease is very uncommon in this area but it was finally suggested to test for it as the lameness seemed to change constantly and fit with the “shifting lameness” description of Lyme. She tested positive for Lyme Disease and my vet suggested 28 days of IV tetracycline twice a day. Halfway through the treatment there seemed to be a slight improvement but she is now finished and seems no better than before starting it. As Lyme is so rare here (Saskatchewan, Canada), I am having difficulty finding information on how to treat Lyme when it has gone undiagnosed for so long and am not sure whether to continue the tetracycline or switch to another antibiotic and what the prognosis is. I would really appreciate hearing about other cases of chronic Lyme or if anyone can pass on the name of a knowledgeable vet as I am running out of ideas with this horse. Thanks very much.
There is a lot of info on Cornell’s website. Just google Lyme disease testing.
There is a horse here who has been treated and retreated for Lyme disease. There is a possibility that the horse’s weight was underestimated the first time, with tetracycline and doxy. The second treatment was with minocycline, we are still waiting to retest. At the moment and for months has been sound.
https://ahdc.vet.cornell.edu/docs/Lyme_Disease_Multiplex_Testing_for_Horses.pdf
I believe the gold standard of treatment is IV oxytet.
I wish I could offer you good news. My stallion was treated at an University for Lymes. 1.5 years later he had liver failure from the Lymes. When they did a necropsy they found the Lymes organism in every organ of his body.
[QUOTE=Laurierace;7479255]
I believe the gold standard of treatment is IV oxytet.[/QUOTE]
[QUOTE=vicarious;7479357]
http://cid.oxfordjournals.org/content/30/1/237.2.full[/QUOTE]
I was referring to horses. Not to mention that article was 14 years old. Hopefully we have learned a lot about the disease since then.
[QUOTE=Laurierace;7479255]
I believe the gold standard of treatment is IV oxytet.[/QUOTE]
This. If vets in your area don’t deal with Lyme’s disease on the regular, this may very well just not be something they know a lot about. Tetracycline is not the heaviest hitter, and if your horse has had the disease for as long as it sounds, it’s not surprising that tetra didn’t work.
There are three different titer counts that a lab should test Lyme’s for: Acute, Sub-Acute and Chronic. Acute demonstrates an active infection within 1-5 weeks, sub-acute is 5-8 weeks, and chronic means the horse has had the infection for at least 8 weeks or longer (at least this is what I remember my vet saying this past winter, the numbers can vary slightly).
Vermont is a haven for Lyme’s disease, so vets around here have a pretty standard way of dealing with it. Titers above a certain level, especially chronic titers, get minimum 10 days of oxitet IV daily. If the count was really high, that might be followed up by a further course of antibiotics given oral for 6 to 8 weeks. When my mare was diagnosed this past December, she tested positive in the chronic titer with a count of 1,248, which is elevated but not super high by any means. I decided to go with the 10 days of oxitet to knock it out. We waited 6 weeks, the retested her, and all counts were down in the negatives. In her case, that was enough. There was another horse, an older gelding, in the same barn who had a chronic titer count of over 16,000 and was almost completely asymptomatic. He set a new record in the vet clinic. That horse required 20 days of IV oxytet daily, plus 8 weeks of antibiotics orally 2x a day, before his counts dropped to acceptable levels.
Each horse is different. Talk to your vet again about treating with oxytet, and def. visit the Cornell website. They know their stuff: it’s where my vet sends all Lyme tests.
The fact that she responded somewhat to tetracycline doesn’t mean she necessarily has/had Lyme. That group of antibiotics has a well-known anti-inflammatory component, so if she’s sore anywhere from practically anything you might easily notice a small, temporary effect.
Given where you live I think Lyme is a long shot; in her age group depending on what she did from ages say, 2-5, arthritic changes from work are a far likelier probability.
Best advice is to see if you can have a full lameness workup done, possibly including bone scan and/or MRI, at a university veterinary teaching hospital.
Good luck!
My guess it was oxy-tetracycline that was used. I have been reading about more horses being treated with minocycline after not responding to other treatments.
chicamux
I have a horse with chronic lyme and it turned out that he had neurologic lyme. The diagnosis came after many joint injections, neck x-rays and a myelogram (sp?). We tested the spinal fluid for lyme and EPM - lyme came back crazy positive. We never treated with oxy-tet only with minocycline. It definitely helped and he was on it for 6 months. We had a recurrance a year later and treated for 4 months. I am now told we will need to treat one week each month forever as well as other treatments due to the lasting effects of they lyme (e.g. fibromialgia like symptoms). The good news is that he is much better, it took time but he is better.
Good luck - I know how frustrating it can be.
Best View, I have a friend with a horse about to start his third Lyme treatment in two years. Do you continue to get titers on your guy? And did you get titers between the two initial treatment periods? Would be interested in hearing more about your experience, and I know she would love to pick your brain. Sadly, I am hearing about more and more horses with chronic Lyme now that Cornell has the better multiplex assay. The old titer certainly gave a lot of folks inaccurate results, but it was what we had at the time. 
[QUOTE=Best View;7480826]
I have a horse with chronic lyme. We never treated with oxy-tet only with minocycline. It definitely helped and he was on it for 6 months. [/QUOTE]
Best, I am the one Crotchety is referring to. Horse tested in low 20,000 OspF July 2012. Treated with 30 days of IV Oxy-Tet along with 28 days of Gastrogard because his most noticeable sympton was being half out of his mind so we were sure he had ulcers. Fast forward 9 months after treatment and his titer was 4800. 4 months later we were again treating him as it had risen to 9600. This time with 2 weeks Oxy then followed up with 6 weeks mino at 1 1/2 times the dose. We’re almost back to square one yet again. 9 months later his titer has risen from 3500 the end of February to 6400 this past week. His increasing agitation prompted me to retest only 6 weeks after the last titer.
Now I’m at a loss to know how to treat. Did your vet make any mention of the toxicity risk with mino for such a long duration? That’s been my only hesitation in keeping him on mino for longer than 2 months.
Sounds like you may finally have this under control so I’m pondering a longer term treatment plan.
