Tick season is upon us - and with it the threat of Lyme disease . There are some 476,000 new cases of tick-related Lyme disease each year, according to the U.S. Centers for Disease Control and Prevention . The disease, which only spreads through the bite of black-legged ticks , can kill although fatal cases are rare. But it’s far from the only fatal disease linked to the tiny bloodsuckers. It’s already shaping up to be a historic tick season with ER visits for bites reaching their highest level in nearly a decade in the U.S. The most have been reported in the Northeast and Midwest, federal data shows. Still, experts warn the worst may be yet to come, as the summer months approach and more people spend more time outside. Tick season typically runs from April to September, peaking in May. But a warming climate has led to longer seasons and expanded the range of ticks further north, in areas people might not expect to encounter them.…