Infectious Canine Hepatitis
Infectious canine hepatitis is a worldwide, contagious disease of dogs with signs that vary from a slight fever and congestion of the mucous membranes to severe depression, severe reduction in white blood cells, and deficiency of blood clotting. In recent years, the disease has become uncommon in areas where routine vaccination is used.
Infectious canine hepatitis is caused by a virus, canine adenovirus 1. Consumption of urine, feces, or saliva from infected dogs is the most common route of infection. Recovered dogs shed virus in their urine for at least 6 months. The virus targets the liver, kidneys, spleen, and lungs, though other organs are occasionally involved. Longterm kidney damage and clouding of the cornea of the eye (“blue eye”) result from immune-complex reactions after recovery from the disease.
Signs vary from a slight fever to death. The mortality rate is highest in very young dogs. The first sign is a fever higher than 104°F (40°C), which lasts 1 to 6 days and usually occurs in 2 stages. If the fever is of short duration, a low white blood cell count may be the only other sign. If the fever lasts for more than 1 day, other signs of illness, such as an increased heart rate, develop. On the day after the initial temperature rise, the white blood cell count drops and stays low throughout the feverish period. The severity of the fever seems to relate to the severity of the infection. Other signs of infection include apathy, loss of appetite, thirst, inflammation of the eyes, and a watery discharge from the eyes and nose. Occasionally there may be abdominal pain and vomiting. The nose and mouth may be reddened or covered with small bruises. Enlarged tonsils and swelling of the head, neck, and trunk may occur.
It may be difficult to get an infected dog’s blood to clot. Respiratory signs may be seen in a few dogs with infectious canine hepatitis. Although central nervous system involvement is unusual, severely infected dogs may develop convulsions from brain damage. Slight paralysis, caused by bleeding in the brain, may also occur. After recovery, dogs eat well but regain weight slowly.
Usually, the abrupt onset and bleeding suggest a diagnosis of infectious canine hepatitis, but laboratory tests are needed for confirmation.
Because of blood loss, blood transfusions may be necessary to treat severely ill dogs. In addition, intravenous fluids are often provided. Your veterinarian will likely recommend treatment with a broad--spectrum antibiotic. Although the clouding of the cornea of the eye usually requires no treatment, the veterinarian may prescribe an eye ointment to alleviate the painful spasm that is sometimes associated with it. Dogs with corneal clouding should be protected against bright light.
Vaccination is the mostly widely used preventive step and is usually given along with canine distemper vaccinations. Annual revaccination against infectious canine hepatitis is often recommended.