Dogs and puppies can pass germs, diseases and worms on to people, but it does not occur often. There are certain precautions that you can take to help prevent this from happening. First and foremost, make sure that the dog or puppy you are playing with looks healthy. Do not touch or contact an obviously sick dog. Make sure that your personal dog has regular check ups and is checked for worms by your veterinarian. Look for obvious signs of disease such as spots missing fur on your dog. Hot spots or places that your dog keeps chewing or biting at can be another sign of infection.