Virginia classifies dogs with a history of attacking people or animals in two ways.
The state labels as “dangerous” any dog that has bitten, attacked, or inflicted injury on another person or domestic pet, or killed a domestic animal.
If a dog is labeled “dangerous,” his owner must obtain a license to possess the dangerous dog. To do this, the owner must present evidence that the dog will either be confined to the owner’s yard (fenced or confined indoors) or muzzled, he must post a sign warning others of the dog, and the dog must be permanently identified with a tattoo or electronic device implantation. If the dog is to be taken off the property (i.e. walked), he must be on a leash and muzzled. Failure to comply with this is a Class 1 Misdemeanor, punishable by up to 12 months in jail, up to a $2500 fine, or both.
The state labels as “vicious” any dog who has (1) killed a person, (2) inflicted serious injury on a person (several bites, serious disfigurement, etc.), or (3) be determined by an animal control officer to be continuously dangerous.
If a court determines a dog to be vicious, it shall be euthanized.
No dogs are per se dangerous of vicious solely based on their breed.
Source: Virginia Animal Law Statutes