The canine adenovirus and the virus that causes canine hepatitis are closely related viruses. In fact, a vaccine for one provides immunity for the other. However, they cause distinct diseases. These two viruses can cause serious issues in puppies and adult dogs.
Type-2 canine adenovirus is usually called simply canine adenovirus or CAV-2 to distinguish it from related viruses. CAV-2 causes a disease called infectious tracheobronchitis, or "canine cough," with symptoms like a hacking cough and fever. The virus can spread through the air after a dog coughs or through pet waste. In most cases, a dog can make a completely recovery with a veterinarian's care.
The canine hepatitis virus is actually caused by another adenovirus, called canine adenovirus Type-1, abbreviated CAV-1. However, it causes very different symptoms. Instead of the lungs, this virus infects other organs, including the kidneys, liver and eyes. While all viruses harm the host by damaging or destroying cells when they reproduce, CAV-1 virus particles are actually toxic in and of themselves. Like CAV-2 infection, most dogs recover, but dogs can continue to pass the virus through their waste for up to a year post-infection.
These viruses are so closely related that the same vaccine prevents both. The vaccine against these viruses are made from attenuated live CAV-2 viruses. The vaccine is usually administered in three- to four-week intervals. The veterinarians recommend giving this shot when a puppy is 6 weeks old. The entire vaccine series typically takes 16 weeks to complete. Typically, vets give these shots along with a puppy's parvo and distemper shots.
These viruses are hardier outside the body than most. Both CAV-1 and CAV-2 can survive for days outside of a dog, and even withstand mild UV radiation, an unusual feat for viruses. However, as little as five minutes at 122 to 140 degrees Fahrenheit can kill these viruses on surfaces. So steam cleaning any surfaces the dog has come into contact with can destroy the virus if your dog has had either virus. The best way to avoid infection is avoidance. Keep unvaccinated puppies and dogs away from other dogs until they complete their shot schedule.