Hepatitis, a disease of the liver that is seen in several animals, including humans, is caused by a viral infection. Canine hepatitis is caused by the virus designated CAV-1 which is seen only in dogs. Humans and other animals are not at risk to contract hepatitis from the CAV-1 virus.
Like many viruses, CAV-1 first localizes and replicates in the lymph nodes and spreads into the bloodstream from there. Once in the blood, CAV-1 attacks several organs, most notably the liver, eyes, and kidneys. Although hepatitis is a very serious disease, not all cases of CAV-1 infection lead to it and not all are serious. Some dogs show few or no symptoms after being infected. Some, on the other hand, especially young puppies, become seriously ill.
Once a dog is infected, there is no treatment that will destroy the CAV-1 virus. There is no cure. There is, however, a very good vaccine that can be given to puppies when they start their series of inoculations. The vaccine has greatly reduced incidents of canine hepatitis in the United States and Western Europe.
Not all cases of hepatitis are caused by the CAV-1 virus. Called idiopathic or periportal hepatitis, these cases of hepatitis are of unknown origin and occur in dogs that are five or six years old in most cases.
Symptoms of both CAV-1 hepatitis and hepatitis of unknown origin can include vomiting, diarrhea, weight loss, jaundice, depression and weakness. Since there is no cure, a vet can only treat the symptoms to the best of his or her ability. Antibiotics are typically given to prevent further infections.
In most cases when a dog contracts CAV-1 the symptoms can be treated to keep the dog comfortable until the virus passes. Once that happens a dog is usually immune to the disease for the rest of its life. Survival rates are high for CAV-1 induced hepatitis with death usually occurring only in puppies.
Some specific breeds (most notably Doberman Pinschers and certain terriers) can develop and suffer from chronic hepatitis. There is no cure for the disease and these animals will have it for the rest of their lives.