If detected early, Lyme Disease is corrected with antibiotics fairly easily. It's has some pretty serious complications if not detected and treated early. (Late stage Lyme Disease requires months of intraveneous antibotics and even then, not always successful.) It can even cause serious mental problems.
We're often bitten by those really small ticks during the summer in rural central Virginia. The small ones make such light footsteps that you don't necessarily feel them walking on you.