Canine Viral hepatitis
Symptoms can vary from very mild to sudden death. Importantly, vaccination has greatly reduced the incidence of this disease in the UK. A hyperacute form can be presented in puppies under 3 weeks, with symptoms including sudden abdominal pain, followed by death within a few hours. This form is rarely seen nowadays.
Early cases are often characterised by marked lethargy. On examination, dogs have a high temperature, inflammation of the tonsils (tonsillitis) and enlarged lymph glands below the jaw. Acute tonsillitis is not common in dogs, and should arouse strong suspicions. Vomiting and/or diarrhoea often then develops, and the dog will lose its appetite. Some dogs may find bright light painful.
The liver is painful and enlarged on palpation. Jaundice and bleeding from the gums may develop as the liver fails. At this stage, the mucous membranes become pale or jaundiced. The dog has a tucked up appearance due to the pain, and about 20% of cases will die. Those that survive the acute stage will recover, although it may take many weeks to regain condition.
A more mild form of the virus exists, where dogs will only develop slight fever, and sometimes diarrhoea, although they will have enlarged lymph glands. Blue eye is a consequence seen in some dogs where the surface of the eye shows a milky blue appearance.
Canine viral hepatitis (formerly called Rubarth’s disease) is caused by a virus, canine adenovirus Type 1 (CAV-1). In Europe, it affects primarily dogs and foxes.
The main source of infection is by ingesting the urine, faeces or saliva of infected dogs. Recovered dogs may shed virus in their urine for up to one year. The virus is resistant to many disinfectants, and can persist in the environment for weeks or months. Dogs are most commonly infected by virus left surviving in the environment rather than direct ‘dog to dog’ contact.
Very young puppies can die quickly, and in a kennel situation, spread can be rapid. The infection gains entry via the mouth, throat and tonsils, before spreading and affecting other organs, especially the liver. Death is common, even with treatment.
Based on the signs (acute forms) and history, your veterinary surgeon may be able to make a diagnosis. This may be more difficult in the mild form, as the symptoms are quite vague. Diagnostic tests do exist, and the CAV-1 virus may be detected in a commercial laboratory, following sampling of the liver or an enlarged lymph node.
There is no specific treatment for canine parvovirus. Treatment is aimed at supporting the patient through the disease and reducing the severity of clinical signs. It is usually necessary to hospitalise animals and intravenous fluids are essential to manage the dehydration and loss of electrolytes. Antibiotics may be used to control secondary infections and other medicines to help support the animal (for example to relieve pain or reduce vomiting) can be given. Infected animals must be isolated from other dogs. Stringent biosecurity regimes should be instituted using isolation and effective disinfectants to prevent the contamination of the environment and people’s clothing, shoes and hands
CAV-1 virus cannot be treated directly, and treatment is limited to supporting the dog during the illness. Treatment may therefore include:
Medication to control symptoms, such as diarrhoea, vomiting, liver failure, failure of the blood to clot.
Nursing care to encourage the dog to eat a special liver failure diet.
Avoidance of all exercise. Many will suffer a severe setback when taken for their first walk on apparent recovery.
Antibiotic treatment may be used to control any secondary bacterial infections.
Infected and in-contact dogs should be isolated from other susceptible dogs and hygienic precautions taken (change of clothing/targeted disinfectants etc).
Prevention is by vaccination. The canine viral hepatitis component is mostly included in the primary vaccination course given to puppies, and often in routine annual boosters. Many vaccines use the CAV-2 strain rather than the CAV-1 (viral hepatitis) strain to protect against viral hepatitis, as this also provides cross-protection for some forms of kennel cough and is less likely to cause “Blue Eye” (oedema of the surface of the eye). Based on your pet’s specific situation, your veterinary surgeon will chose a protocol to best meet your pet’s needs. An up-to-date vaccination is usually obligatory before going to dog shows and many kennels.