We also get the "crud" every year in Gold Canyon, AZ. I have always thought it was a result of so many people from so many areas all congregating in the same area. We get exposed to strains that we have not developed immunity to. Colds and flu virus continually mutate so every year, we each bring a slightly modified version with us.
Before I retired, I spent time in project work camps around the world where workers came from many different places and we always had a version of the "crud" that hit just about everyone.
Don't believe there is a real sure fire cure since Viruses cannot be easily treated. The only thing I have noticed is that when I started getting my yearly flu shot, I caught the Crud less often and was not as sick for so long a period.