Living in Connecticut and being somewhat sporty and outdoorsy, one thinks of Lyme Disease. Both of my good balloon friends have had it. Another friend from down in Ivoryton has had it 4 times. So far, I seem to have escaped.
However, being 45 years old, and tossing my sorry rear end around on a yoga mat and at jazzercise 4-5 times a week, I am not sure if I would be able to discern the acute symptoms from my general aches and pains from exercising a lot without a lot of down time to recover.