OK here's one from a vet..<G>. IMHO, Lyme (and it is Lyme, not Lyme's)
disease is overdiagnosed in horses.Note: I am not saying it doesn't exist, I
am saying it is not as common as a lot of folks seem to think.
It is overdiagnosed in people as well. The MD who was instrumental
in the original "discovery" of Lyme disease, who heads a Lyme disesae clinic
at NE MEdical center, which takes referrals only, said in an interview that
only about 1/3 of the patients referred to him actually had clinical Lyme
disease. The rest had other types of joint disease or occasionally other
systemic problems. This in human, who can answer such questions as "where
does it hurt", and who have less hair and could presumably notice both deer
ticks and subsequent skin rashes.
The currently available serologic tests for Lyme disease, as was
pointed out, indicate exposure and not infection. One of the coastal
islands of Massachusetts has an equine population with positive Lyme titers
in the vast majority of them.
So, what to do? Lyme disease becomes a diagnosis of elimination.
Rule out every other cause of lameness, and then treat with appropriate
antibiotics. Resolution of signs *may* indicate that Lyme disease was the
cause.
In the case that started the current discussion, I am somewhat
puzzled at the association of sof tissue sensitivity in seveal areas being
considered a sign of Lyme disease. That is not a common clinical finding. I
would continue to look for other causes while treating for Lyme in this horse.
Just my 2 cents.
--CMNewell, DVM