They don't jump. I live in a forest and had hundreds of those, but not a single one ever jumped. It's a myth. They only let themselves drop if something touches the leave under which they are hiding.
Concerning infected ticks: Northern germany has a few but it's not as bad as in southern germany. From all the ticks I had I never catched a disease. Only my father suffered borelia once, but after 2 weeks of antibiotics it was gone.