Canine Infectious Hepatitis is a highly contagious viral disease that affects the liver and other organs, and is caused by Canine Adenovirus type 1 (CAV-1). Canine Infectious Hepatitis is spread only among domestic dogs and other wild canids which include wolves, coyotes, and foxes. Signs range widely, from mild to severe, including vomiting, loss of appetite, light-colored, mucus laden, and/or loose stool, and tense or distended abdomen.
The liver is a vital organ that performs has many functions essential to sustain life, including manufacturing blood proteins, fats, and clotting factors, storing energy as glycogen to be used as energy, storing fat-soluble vitamins and iron, detoxifying drugs, chemicals, and toxic metabolic byproducts, secreting bile for proper digestion, and filtering harmful bacteria and other pathogens from the blood. Any disturbance of the liver and its vital functions are a very serious matter, and should be considered a medical emergency if suspected.
A dog can become infected with CAV-1 through direct contact with an infected animal or contaminated objects (e.g., food dishes or feces). Other modes of transmission are by inhalation or bites from infected insects such as fleas, ticks, and mosquitoes. Incubation period of the virus is about 4-7 days, after which replication of the virus reaches systemic numbers sufficient to shed in the feces, urine, saliva, and mucus membranes, making this period the most contagious period.CAV-1 travels from the initial site of infection to the lymph nodes, then proceeds to the bloodstream, eventually attacking the liver, kidneys, eyes, and other organs, where it can cause extensive cellular damage and loss of organ function.
Most dogs with healthy immune systems will recover spontaneously following a bout of Canine Infectious Hepatitis (typical course of about 1 week), sometimes with the necessary help of supportive care with IV fluids, antibiotics, antiemetics, and liver supportive medication. Young puppies, especially those that are unvaccinated, are most susceptible to serious complications of Canine Infectious Hepatitis, although serious complications can occur in any age patient. These complications include: hemorrhage from the nose and gums, hemorrhagic vomit and diarrhea, free fluid in the abdomen and fluid leakage due to extensive liver damage, disorientation, seizures, coma, and death, usually within five days. Sudden death can also occur within a matter of hours, particularly in infected, unvaccinated puppies puppies, with no previous signs.
About 25% of dogs with acute Canine Infectious Hepatitis, most commonly in infected dog those under six months of age, develop “blue eye,” a clouding of the cornea of one or both eyes caused by antibodies that attach to the virus present in the eye. Resultant inflammation and fluid accumulation in the eye’s interior subsequently is responsible for the cloudy/bluish appearance. Blue eye typically does not last for more than six months, but longer than this may cause potentially cause permanent eye problems that may predispose the patient to uveitis or glaucoma.
A diagnosis of Canine Infectious Hepatitis begins with recognition of typical clinical signs, which include vomiting, diarrhea, jaundice appearance, distended, firm and/or painful abdomen, fever. Important historical information includes age of the patient (puppies are most susceptible), recent exposure to infected dogs, and overdue or absent vaccines. A battery of blood work that includes CAV-1 serology, serum chemistry, urinalysis, and complete blood work confirms the diagnosis.
Regarding treatment for Canine Infectious Hepatitis, the virus will typically eventually run its course, but aforementioned supportive are sometimes useful in stabilizing the patient to enable the mounting of an effective immune response to hasten recovery. Blood and/or plasma transfusion are sometimes necessary in cases of severe complications, but this represents the minority of cases. Prognosis in the absence of sever complications tends to overall be fair to good.
Prevention of CAV-1/Canine Infectious Hepatitis is very achievable with a 95% effective vaccine. Vaccination typically begins at 6-8 weeks (the age range when maternal antibody protection begins to break down), then boostered 1-2 more times at 2-3 week intervals. Vaccine protocols will vary between individual veterinarians.
Roger L. Welton, DVM
Founder and Chief Editor, Web-DVM.net
President, Maybeck Animal Hospital
Article updated 9/17/2012