*Viral: Epitheliotropic viruses E.g. [[Equine Viral Arteritis|Equine arteritis]], [[Canine Distemper Virus|Canine distemper]]. | *Viral: Epitheliotropic viruses E.g. [[Equine Viral Arteritis|Equine arteritis]], [[Canine Distemper Virus|Canine distemper]]. |