Results from a single test can be deceptively low, especially if the horse has a chronic infection or hasn’t yet mounted a large- scale immune response.

Tinsley explained that while her experience with Lyme was very limited--she had trained and practiced in areas where the disease is not common--recently she had been speaking with colleagues from the Northeast, and one had mentioned that he had seen a few cases of headshaking associated with Lyme. In people, Tinsley continued, the infection has been shown to cross over into the central nervous system, causing headaches and neuropathic pain---sharp, stinging sensations such as those that might cause a horse to flip his head as if he were being bothered by bugs. She had shared

We still have lingering, unanswerable questions about what Whisper went through that year: Were the headshaking and Lyme disease really connected? Why did it take so long for the antibiotics to work? Is the problem gone for good? Tinsley has warned me that signs of Lyme disease can return years later. So I’ll always have a lingering worry that I’ll get another call from the barn one day. But if that day ever comes I’ll take solace in the fact that persistence paid off once, and I’ll resolve to not give up until my horse is better again.