My greyhound came down with a version of Lyme (it mutates) three years ago. He was hospitalized in one of the best veterinary facilities in Southern California, with great specialists. Even so, he almost died several times. It took weeks of tests and consultations with veterinary specialists back east to figure out what it was, and then more time to find the precise combination of antibiotics to knock it down. Notice I didn't say "cure." It is now dormant in his bloodstream -- we found that out after he crashed twice after the initial "recovery." He's on doxycycline and prednisone for the rest of his life.

And yes, it was enormously expensive, and the pet insurance found ways in which to avoid paying most of the bill.