How well do PTZ cameras handle very dusty outdoor environments?

I’m interested in hearing from people who have used professional PTZ cameras such as Panasonic or Canon’s CR-N series in really harsh outdoor environments.
In particular, I’m thinking about motorsport / motocross / dirt tracks, where there can be a huge amount of dust, sand and dirt in the air.
How have your PTZ cameras held up in these conditions?

Have you used cameras that aren’t specifically designed/rated for harsh outdoor environments in these conditions?

Also, have you found any practical ways of protecting the camera?

Thanks