A reader/listener from East Hampton, Long Island, who says he (or she) had Lyme disease in the mid-1980s, sent along these thoughts:

Four somewhat interrelated factors may have coalesced to make Lyme increase in the past two decades:

1. The expansion of second homes into formerly isolated rural areas.
2. A large spike in the deer population as food from gardening has increased, while hunting has diminished.
3. A concomitant increase in field mice populations, which, like deer, are an essential vector for the deer tick.
4. The compassionate removal of feral "house cats" from the wild. These cats are capable of catching and eating 100 field mice per day, which ordinarily would keep the mouse and tick populations down.

Each one of these human-centered actions was considered benign in itself; but taken together they may have caused an epidemic.

I don't know whether scientists have studied this possibility, but the outbreak of hysteria culminating in the Salem witch trials may well have been modulated by the Lyme spirochete, with its many attendant mysterious physical and mental symptoms, as settlers began clearing land in New England  in the 1600s.