Is it permissible for a veterinarian to touch dogs—including their mouths and impure saliva—for the purpose of treating them, and what should he do if some of the dog's saliva gets on his hand or clothes?

Dogs are either permissible to keep or not permissible. Those permissible are hunting dogs and guard dogs; anything else is not permissible. There is no harm in treating dogs, whether permissible or not, because they are living creatures. Both types are impure, and one must be careful to avoid their saliva. One should advise anyone who keeps a dog for a purpose not permitted by Islamic law, and clarify to them that this diminishes their reward by one qirat every day, and that angels do not enter a house that contains a dog or an image.