It is progressive and dangerous.
It will begin with one cute puppy.......usually for companionship. You will not realize that you have been infected even when you begin trying to convince your family that buying cute collars and doggy outfits is more rewarding than buying groceries.
You may not recognize the symptoms even when 90% of your snail mail consists of pet catalogs & cute doggy boutiques. By the time the virus has taken firm hold, you will have reduced your yard to a safe area that can be enjoyed by your dogs. You will be trying to sell the kids swing set to pay for the latest grooming gadget.
Your computer will threaten to crash because of the huge amounts of dog web sites, canine forums, programs, breed lists, advice lists, dog images, and canine health bookmarks that have filled all available space.
You will "borrow" from your child's college fund to add more memory. This virus will take over every room of your house in the form of fliers, catalogs, magazines, dog toys, dog beds, crates, dog food and doggy art.
You will seriously consider a second mortgage to take advantage of dog supply sales or, even worse, cute doggy clothes!
Depression will set in immediately after adopting out your last puppy. Your own dogs will worry about you. There is no cure.
Thankfully, there are groups where you can talk to others that have been infected and who will understand you. With luck they'll also know of a really good sale on dog food & cute outfits.