What is it?
Infectious Canine Hepatitis is a life threatening disease. It is caused by a virus called Canine Adenovirus type 1 (CAV1). The virus causes liver and kidney disease, usually in weaned puppies and young, unvaccinated dogs. 10-30% of infected dogs may die.
The virus is spread in the urine of infected dogs. The virus gains entry through the mouth or nose, usually from an environment that is contaminated by the faeces, urine and bodily fluids from an infected dog, rather than direct contact between dogs. The virus invades the tonsils, and from there it makes its way to the liver and kidneys. It multiplies within the organs and destroys the liver and kidney cells. Very young puppies can die quickly, and spread may be rapid in a kennel environment.
Recovering dogs may develop chronic kidney disease and ‘blue eye’ (corneal oedema) as the immune system tries to clear the infection.
Why is it important?
There is no cure for CAV1 infection. Unvaccinated dogs are vulnerable to contracting CAV1. Some affected dogs may not show signs of being ill but they may still shed the virus. Many dogs that are affected by acute liver disease will die. CAV1 may cause acute kidney disease 20% of dogs develop 'blue eye' or corneal oedema Sudden death may occur Canine Adenovirus 1 is closely related to Canine Adenovirus 2 which causes kennel cough. Affected dogs may die; if they recover, they may shed virus in their urine for up to a year, as the virus is able to settle in the kidneys. These dogs remain highly contagious to other dogs.
What happens to the dog?
Usually, infection is only seen in unvaccinated dogs, or those who have not completed their primary courses. The signs of CAV1 infection include: Lethargy Not eating Bleeding from or bruising of the gums Cough Abdominal pain Bloody diarrhoea Seizures Corneal oedema (blue eye) Examination of the dog by your vet may reveal Fever Red, congested gums, pale gums, or bleeding from the gums Enlarged tonsils Enlarged, painful liver Enlarged lymph nodes
How do we know what is going on?
Blood tests may show rising antibody levels to CAV1 virus with 2 samples taken 2-4 weeks apart. For urgent diagnosis then the virus can be tested for in the blood, urine or tissues of the dog.
Initially the dog’s white cells and platelets (involved in blood clotting) are low. The dog is at risk of internal bleeding. Gradually the levels of white cells increase in recovery. The liver and kidneys will show signs of damage, which may be permanent.
These dogs are often very sick, and CAV1 infection can appear like other diseases, such as canine distemper, leptospirosis, other liver diseases, parvovirus, rat poisoning, or obstruction of the gut due to a foreign body.
What can be done?
Treatment is supportive, with fluid therapy, broad spectrum antibiotics to prevent secondary infection, and blood transfusions if necessary. Recovered dogs may be more susceptible to kidney infections Recovery and weight gain may be slow. Infected dogs must be isolated and the premises thoroughly disinfected. In acute (sudden onset) cases, the dog may not survive despite intensive treatment.
How do I protect my pet?
In the event of an outbreak, CAV1 is quite resistant to disinfection. Bleach at appropriate concentrations will kill the virus. Vaccination is crucial to preventing infectious canine hepatitis. Vaccination protocols will vary, but it is usual practice to give the first puppy vaccines at 8 and 10 weeks and then a booster after 6-12 months. If the first vaccination is given before 8 weeks, then the second vaccination should not be given until 10 weeks. If the puppy’s mother was vaccinated, antibodies against CAV1 will be passed on to the puppy and these antibodies will be expected to last for 5-7 weeks. Antibodies from the mother protect the puppy, but may also interfere with the puppy’s response to the vaccine, so a second vaccine at 10 weeks ensures that the puppy’s immune system responds to the vaccine. Vaccines containing CAV1 have been linked with development of eye problems and kidney disease, so most routine vaccines contain CAV2. Antibodies to CAV2 also protect against CAV1 but without the harmful side effects. The immune system is then able to recognise the CAV1 virus and stop it causing harm to the dog.
