By Dr. Becker
Infectious canine hepatitis, or ICH, is caused by the canine adenovirus type 1 (CAV-1). The infection can cause damage to cells throughout a dog's body, especially those located in the liver, kidneys, and eyes.
At one time, there was a vaccine available to protect dogs from type 1 adenovirus, but it was discontinued because it caused a condition called blue eye, which is a protein deposit that resulted in a bluish tint to one or both eyes of vaccinated dogs. These days, we vaccinate against canine adenovirus type 2 (CAV-2), which is a kennel cough virus, and the same core vaccine provides cross-protection against canine adenovirus type 1 as well.
Outbreaks of infectious canine hepatitis had not been reported in the U.S. for at least a dozen years until the fall of 2012, when a litter of puppies in the northeast became infected.
How the Infection Is Transmitted
Canine adenovirus type 1 is found all over the world, and is spread by bodily fluids, including nasal discharge and urine. The most common method of transmission is direct contact with an infected dog, especially the dog's urine. Contaminated kennels or living quarters, bowls and other supplies, and human hands and shoes can also transmit the virus.
Dogs that recover from infectious canine hepatitis can shed the virus for up to a year in urine, which makes it very difficult to determine exactly what locations might be contaminated.
The infectious particles enter a dog's body through the nose or mouth and invade the tonsils, where the virus replicates and then infects nearby lymph nodes. The cytotoxic particles spread from the lymphatic system to the bloodstream in about a week. Once travelling through the blood, the virus infects other target organs, including the liver, kidneys, and eyes, with the liver almost always being the most severely affected organ.
Symptoms of Infectious Canine Hepatitis, and Dogs Most at Risk
As is the case with parvovirus, unvaccinated puppies of all ages are at risk for infectious canine hepatitis, and certainly unvaccinated adult dogs as well. However, the disease is significantly more prevalent in puppies under a year of age. Death can occur as soon as two hours after the initial signs of infection. And in fact, death can be so sudden that it may seem the dog has been poisoned.
Symptoms of infectious canine hepatitis include acute nausea, vomiting, loss of appetite, light-colored stools, and painful abdominal swelling. More severe cases can involve high fever, tearing of the eyes, tonsillitis, laryngitis, swollen lymph nodes, jaundice (a yellowing of the skin), and pale gums, tongue, and nose.
Some dogs also develop blue eye, which is the same condition that caused the CAV-1 vaccine to be discontinued several years ago. The bluish tint is the result of viral particles in the eye, and the condition often resolves on its own over time. But occasionally, blue eye will progress to a more significant eye disease like glaucoma.
Diagnosing and Treating ICH
Since symptoms of infectious canine hepatitis are similar to symptoms of several other disorders, including distemper and a variety of forms of toxicosis, it's important for your veterinarian to confirm a diagnosis of ICH.
A common early sign of ICH is a low white blood cell count, but this alone is not enough for a confirming diagnosis. Your vet will want to perform a urinalysis and a blood test to look for antibodies against canine adenovirus type 1, which can be detected using immunofluorescent techniques. An enzyme-linked immunosorbent assay (ELISA) test can also be conducted to check for viral particles in the dog's feces.
Unfortunately, as with most viral diseases, there is no specific treatment for infectious canine hepatitis. The focus is on supportive care and alleviating individual symptoms. If your dog has tested positive for the virus, your veterinarian will most like place an intravenous (IV) catheter to provide fluids and glucose. Some dogs receive eye drops to help alleviate eye irritation. Blood transfusions may be necessary if there's significant hemorrhaging, and many infected dogs require hospitalization.
Holistic vets typically supplement conventional supportive care with homeopathic nosodes, colostrum, and herbal liver, kidney, and eye support.
The very best treatment for infectious canine hepatitis is, of course, prevention. Since the disease has now reappeared in the northeast part of the U.S., Dr. Jean Dodds recommends a CAV-2 vaccine at puberty, at least for puppies living in that part of the country.1 Vaccinating puppies against type 2 adenovirus causes a period of immunosuppression that can last at least 10 days. This problem does not occur with adult dogs who receive the vaccine, which is why Dr. Dodds recommends that we vaccinate puppies at puberty and not before.