I 've had my share of ticks, counted and removed 18 after one patrol in Belize, some of the boys had more.
I've never had an adverse reaction, I have never met or known anyone who's had Lyme disease either.
I've swum in rivers and crossed swamps, and never got Weil's disease.
These "risks" make great headlines for the media who are generally uninformed as to the likelihood or chance of it striking. Obviously it's bad luck if you get caught out and it never hurts to take sensible precautions.
For the record I have never caught malaria, been struck by lightning, bitten by a shark, or stabbed by a lunatic, maybe I should get out more!