Why do we need to vaccinate our dogs? (Part 1)

Part 1 - The DHP vaccine

 The ‘DHP’ vaccine is part of the core vaccines recommended by vets. In this blog we will discuss the three diseases covered by the DHP vaccine, the classical symptoms for each, possible treatments and the recommended vaccine schedule. It is often easy to take for granted that we now don’t see these diseases as often in the UK but this is all thanks to vaccine development over the years!

Distemper

Caused by the Canine Distemper Virus this disease is highly contagious and is often lethal. It is present in dog populations across the world as well as being a threat to wildlife. Luckily, thanks to the development of a vaccine in the 1930s, distemper is now very rare in the UK. 

It spreads via direct contact with bodily fluids or aerosol droplets from infected dogs (much like the flu virus spreads). The symptoms can range from vague lethargy and fever to respiratory signs, vomiting, diarrhoea and neurological signs. The dog’s immune system is weakened and they are susceptible to getting secondary bacterial infections like pneumonia. Some dogs do recover but up to 50% will die from the disease and its complications. There is no treatment for the disease except for supportive care to help ease the symptoms. 

Infectious Canine Hepatitis

Infectious canine hepatitis is caused by the Canine Adenovirus (CAV). There are two strains of CAV which cause different symptoms. CAV-1 is spread via infected urine, faeces and saliva. It causes infectious canine hepatitis which causes an enlarged inflamed liver which can progress to liver damage. The first signs are often lethargy and fever which progresses to vomiting,  diarrhoea and jaundice. As their liver fails there can also be bleeding from the gums and anaemia. 

There is no specific treatment so, as above, treatment is just supportive. About 20% of those affected die from the disease. Those that do recover can be left with damage to their kidneys or eye problems like ‘blue eye’.

Another variant, CAV-2, is spread via the respiratory system and is one of the agents that can cause kennel cough. Normally this will resolve with time but can cause more serious illness if there are secondary bacterial infections. 

Parvovirus

Canine parvovirus has only been present in the UK since 1978. Unfortunately, parvovirus is still common in the UK especially if puppies have originated from unscrupulous breeders. It is most common in young puppies but older dogs can still develop the disease. 

Like many of these diseases lethargy, not eating and a fever are often the initial signs. This will progress to foul smelling bloody diarrhoea and vomiting. It can be tested for easily with a faecal swab test (similar to a COVID test but at the other end!). 

There is no specific treatments for parvovirus and, despite best efforts, it is often fatal. There is a novel therapy that using omega interferon which is a protein that helps to stimulate the immune system. This has been shown to reduce mortality by 4-6 times but is not always widely available.    

Vaccine schedule

The saying prevention is better than cure is certainly true for these potentially fatal diseases. Your puppy should ideally get one DHP vaccine at 6-8 weeks of age and another 2-4 weeks later so that the 2nd vaccine is after 10 weeks of age. This is because your puppy will have some antibodies from their mother which can mean that they don’t develop as good an immune response if they are vaccinated too early. A booster is then given 12 months after completion of their primary course and then once every 3 years. 

Alternatively, instead of a booster, you can choose to titre-test your dog. Your vet can take a blood sample and test this for antibodies to the above viruses. Studies have suggested antibodies can still be present 3-15 years after vaccination. Despite this, booster vaccinations are valuable as they do just that – boost the number of antibodies in your dog's blood! 

If you have any questions or concerns about vaccinating your dog please discuss with your own vet and always follow their recommendations.