Lyme disease does exist on the west coast, including in the Bay Area. A friend in Los Altos got Lyme disease from a tick in her yard. This is the worst time of year for ticks in the Bay Area. I've picked off over 100 ticks while doing field work in Henry Coe State Park. The one advantage we have on the west coast is that our ticks are larger and you usually notice when one starts crawling on your skin and especially when one bites you.