Infectious Canine Hepatitis

Infectious canine hepatitis is a contagious, worldwide disease of dogs. Signs can range from mild fever and mild inflammation of the membranes inside the mouth, nose and eyes, to severe illness involving weakness, a sharp drop in white blood cells, and blood clotting problems.

The disease is now uncommon in areas where routine vaccination is used.

Infectious canine hepatitis is caused by canine adenovirus type 1. Dogs are usually infected by ingesting urine, feces, or saliva from infected animals. Dogs that recover can continue to shed the virus in their urine for at least 6 months. The virus affects the lining of blood vessels and can damage the liver, kidneys, spleen, and lungs, though other organs can also be involved.

After recovery, some dogs develop long-term kidney damage or “blue eye,” a cloudy appearance of the cornea caused by immune reactions.

Signs vary widely, from mild fever to death, with young puppies at highest risk. The first sign is typically a fever above 104°F (40°C), which can last 1–6 days and sometimes occurs in two phases. If the fever persists, other signs such as increased heart rate can appear. White blood cell counts drop early and remain low during the fever. Blood clotting problems can lead to uncontrolled bleeding.

Other signs include lack of energy, loss of appetite, increased thirst, eye inflammation with discharge, vomiting, and abdominal pain. The nose and mouth can appear red or bruised, and swelling of the head, neck, and body can occur.

Respiratory signs are uncommon, but severe cases can involve seizures or mild paralysis (inability to move) due to brain bleeding. After recovery, dogs typically regain appetite but might gain weight slowly.

Diagnosis is based on signs and confirmed with lab testing. Treatment can include blood transfusions for severe blood loss, IV (intravenous) fluids, and antibiotics to treat secondary bacterial infections. Eye discomfort may be treated with ointments and protection from bright light.

Prevention relies mainly on vaccination, which is commonly combined with canine distemper vaccination. Regular vaccination according to your vet's guidance is the best way to prevent disease.