If you get a puppy that is already carrying a disease it may never recover to full health. A healthy puppy should have bright clear eyes and a clean shiny coat. Avoid taking on a puppy with a large pot-belly or a dull scurfy coat. Take the puppy to your own vet for a check as soon as possible. Your vet can tell you if the puppy looks healthy and may be able to detect problems that the puppy was born with which might cause problems in later life.