Parvo Virus - What is it and why should we vaccinate?

Parvo virus is a common disease that most vets in the world have unfortunately had to treat.  Just the mention of the word fills me with horror, as it’s such an awful disease with a very high mortality rate and is sadly such a preventable disease.  Earlier this year Hawkes Bay had a parvo virus outbreak where numerous cases were treated in this area, with many dogs losing their lives unnecessarily.


What is it and how is it spread?

Parvo virus is highly contagious preventable virus that most commonly affects dogs between the ages of 6 weeks and 6 months, although it can affect unvaccinated dogs at any age.  Dogs are most susceptible after the stresses of weaning, an immature immune system and when maternal antibodies from feeding off colostrum from their mother have waned.  The virus is extremely hardy and can survive in high and low temperatures, is resistant to drying and is difficult to kill.  It can survive in the soil for up to a year and in the right conditions in organic material, can survive several years!  Your dog may be exposed to parvo virus by direct contact with an affected dog, via infected faeces in the environment from an infected dog, or indirect contact with infected material being carried on shoes/clothing/cars etc.  Only a small amount of virus is required to cause disease in susceptible dogs.  Once the dog has been exposed to parvo virus it takes around 3-10 days for symptoms to start.  The dog will then start shedding virus 4-5 days after exposure. The virus first starts to attack the glands in the throat and then spreads to the rest of the body targeting rapidly dividing cells in the body, such as white blood cell which are responsible for fighting disease.  It also damages the cells lining the intestinal tract so that blood and protein and fluid leak into the intestines causing severe dehydration and bacteria from the gut can get into the blood stream which can cause a serious infection known as septicaemia.


What are the symptoms of parvo-virus?

  1. Anorexia (off food)
  2. Lethargic (sleepiness)
  3. Vomiting
  4. Diarrhoea – often bloody and foul smelling
  5. Fever or a low body temperature


How do we diagnose parvovirus?

Parvo virus is can be strongly suspected when an unvaccinated puppy or adult dog presents with the above clinical signs.   Diagnosis however can be confirmed by using a test that can detect parvovirus particles within a faecal sample. 


How do we treat parvo virus?

Left untreated parvo virus has a mortality rate of up to 90% within 2-3 days of exposure!  Intensive treatment can improve this from 5-20% mortality.  Parvo is a virus so there is no specific treatment.  The main aim of treatment is to support the dog until their own immune system can kill the virus.  Treatment involves intensive fluid replacement by an intravenous drip to replace all the fluid and electrolytes lost in the diarrhoea and vomit, medications to control vomiting and diarrhoea, antibiotics to treat secondary infections, nutritional support and intensive nursing.  Patients need to be treated in strict isolation and nursing staff need to be thoroughly disinfected prior to leaving the dog to prevent spread to other patients.  As treatment is so labour intensive and involves intensive care, veterinary costs can quickly escalate.  Some owners try to treat their dogs at home in view of expense, but it’s often hard to provide adequate care and many dogs will still die of dehydration and overwhelming infections.   If the dog recovers, they can still spread parvo virus in their faeces for up to 3 weeks into the environment.  In addition, your property may remain a source of parvo virus infection to any future unvaccinated dogs/puppies for many future years!


How do we prevent Parvo virus?

Most puppies are protected by antibodies obtained from their mothers’ colostrum (if vaccinated) for the first few weeks of life.  However, this protection starts to wane from 8-12 weeks of age and combined with an immature immune system, makes them very vulnerable to parvo virus infection during this period.  Vaccination of puppies should therefore start at 6-8 weeks of age.  Parvo vaccination is a very safe effective means to prevent infection and vaccine reactions are very rare.  Some puppies however, may have very high level of maternal antibodies up to 12 weeks of age and beyond, which may prevent them responding adequately to the vaccination. The World Small Animal Vaccination Guideline Group therefore recommends vaccinating puppies every 2-4 weeks until 16 weeks of age.  It is then recommended that dogs have an annual vaccination to also catch those dogs that haven’t responded adequately to the primary vaccination course.   From this point, most dogs will have adequate protection against parvo virus for at least 2-3 years.  Rottweilers and Dobermanns are believed to be poor responders to vaccination making them more susceptible to parvo virus – however this is currently unproven. 



AnimalCare 2002 Limited

Animal Care Vets is actively involved in our local community. We support a number of charities, including the SPCA. We also care for the Hawkes Bay Police dogs. Our customers know by experience that they can rely on us for sound advice on treatment options and that their pet is in the very best hands with our team.