Unfortunately, dogs still get the mange. It may not happen to our pets too often since they are so well taken care of. However, if your neighbors don't take care their dog or a stray comes into the area then mange can be transferred. It can be transferred if you pet a dog with mange and then pet your dog afterward. Should always wash your hands after petting a strange animal.
Mange is curable and treatable. I just wouldn't treat it with something that could be eatable and make the dog sick.
I am a firm believer in Brewer's yeast for coat control. It is a great supplement and keeps coats soft, smooth, and less shedding. It helps with Flea control as well. Which may be another source of the mange.