Thanks, G and K and smrobs, I appreciate the kind words. :)
Well, her appetite has improved, but she still has that sleepy look and shuffles around. I guess we'll see what the morning brings.
My vet said ticks and also mayflies are carriers. I also read that standing water can become infected and horses can contract the disease from drinking the water. It makes sense because we have had a very wet spring and part of our pasture flooded.