There are 2 types of illnesses that I know of.It could be Distemper or Infectious Canine Hepatitis. Distemper usually affects puppies but older dogs can be affected too. It can affect your dog's intestines and respiratory. Dogs can die with or without treatment, and might even leave your dog with nervous system disorders if he's cured. He might have from 2 days up to 2 weeks without proper treatment.
OR He might have Infectious Canine Hepatitis. It's rare, but only can be contracted if your dog hasn't gotten shots for this already. It very contagious among dogs only. Liver swelling is very common in this disease. Dogs with this rarely survive...but immunizations to help build antibodies can help fight it. After that, it just takes time to heal. Kidney problems could occur after recovery though.
OR He might have Infectious Canine Hepatitis. It's rare, but only can be contracted if your dog hasn't gotten shots for this already. It very contagious among dogs only. Liver swelling is very common in this disease. Dogs with this rarely survive...but immunizations to help build antibodies can help fight it. After that, it just takes time to heal. Kidney problems could occur after recovery though.