If an animal bites you, you may be immediately worried not only about your injuries, but the bacteria and viruses that could have been transmitted to you. If a dog has bitten you and it was a family pet, you may already know that it had vaccinations. However, if you didn't know the animal and have to be treated, the owner needs to be found to verify the pet's vaccination record. If this isn't possible, you'll need to be vaccinated against a number of potential diseases, such as rabies.
Once you're in a position where you are healthy enough to speak with the owner about the case, you need to know if the owner is going to be held liable for the pet. A few things need to be determined. First, who is the owner? Does the state enforce strict liability against that person? If so, then the owner will be held responsible for your injuries regardless of what he or she did or didn't do to protect others from the pet.
It will also need to be determined whether or not the owner know about the animal's dangerous behaviors. Has the dog bitten others before? Had it been trained to attack? If you can prove that the owner knew the dog was dangerous and did nothing to protect others from the dog's vicious attacks, then you have a strong case.
Sometimes, owners won't be held responsible for the injuries to other people. This is true if, for instance, someone was warned to stay away from the dog but then the person tried to pet it, anyway. In that case the person could be said to be negligent, so the injuries were one's own fault.
Source: FindLaw, "Dog Bites and Animal Attack Overview," accessed June. 01, 2015