5 Facts To Know About Parvovirus

WED 31 JAN 2018

This article is written by Pet Circle veterinarian, Dr Kim Chainey BVSc.

Canine parvovirus (CPV-2) is a highly infectious virus that causes disease and death in puppies and dogs across Australia every year. It is extremely robust, meaning it can survive in the environment for prolonged periods of time, acting as a potential source of infection for other dogs.

How does Parvovirus cause disease?

It's a virus that targets the rapidly dividing cells in the body such as the cells in the digestive tract and bone marrow. In the gut, the virus prevents absorption of important nutrients leading to diarrhoea, vomiting, dehydration and nausea. This altered gut barrier leads to bacteria crossing into the bloodstream resulting in shock, sepsis and potentially death. In the bone marrow, the virus knocks out the cells of the immune system, further diminishing the animal's ability to fight off the infection. If left untreated, mortality rates can exceed 50%.

So what do you need to know?

1. Parvovirus is not just a disease of puppies.

Parvovirus most commonly infects puppies after weaning at the age of 4 - 12 weeks. Why this time? This is when antibodies that puppies receive from their mother's colostrum (the first milk after giving birth) are starting to wane, leaving puppies at risk.

While the disease is more severe in young puppies due to their developing immune systems, we can also see Parvovirus in puppies up to 6 months of age, in adult dogs and even cats!

In fact, it's thought that the canine Parvovirus originated from a cat virus by mutations in the late 1970's when it first appeared in dogs. Today, there are multiple variants of Parvovirus (CPV-2a, 2b, 2c) that can also infect cats and cause clinical illness similar to what we see in dogs. But don't be alarmed, your standard cat and dog vaccinations will provide cross-protection against all Parvovirus variants. And thankfully, it cannot be transferred to humans.

2. Parvovirus is one of the most contagious viruses in the world.

Parvovirus doesn't have to be transmitted via contact like other viruses - it can be spread by a number of different routes. Typically it is shed in the faeces of an infected animal, and is then ingested or inhaled by susceptible animals. It can also be spread indirectly by contaminated shoes, clothes and objects.

In short, Parvovirus is everywhere, and will remain unless regularly disinfected. It can survive freezing temperatures, and can even survive many household disinfectants. It can even remain infectious for at least a year in the grass and soil and on towels and bedding. This means that you can also easily pick up the virus on your clothes and shoes from an infected environment and transmit the virus into a new location.

3. Parvovirus is the number one reason why puppies can't go outside until they're vaccinated.

Ever wonder why your vet told you not to take your new puppy out into the big wide world until they are fully vaccinated? It's not just your vet being overprotective - parvovirus is a very real risk for unvaccinated puppies.

But why do they need so many puppy vaccinations? There are multiple factors at play here so stick with me for this bit.

Firstly, puppies and kittens rely on antibodies in their mother's milk to protect them against infection while their immune systems develop. These anntibodies start to wane and are generally no longer present by 6 - 16 weeks of age.

Important point: The age at which these antibodies disappear is different for each individual puppy.

So while these antibodies are vital to protect puppies against infection, they can actually interfere with the animal's ability to effectively respond to vaccination. This is the very reason puppies and kittens require multiple vaccinations - to capture the right time for that individual animal to effectively respond and be protected.

High-risk areas such as dog parks and outdoor public areas are an unnecessary risk until your best friend has had all their vaccinations. It's advisable to keep pups isolated from dogs with an unknown vaccination status or disease history until they are fully immunized. Many veterinarians advocate waiting at least 1 week following their final vaccination to be safe.

4. Summer poses the biggest risk.

Research has shown that summer carries the highest risk of death from canine Parvovirus. Interestingly, a recent Australian study also showed that autumn may have a higher risk for seeing the most number of cases. This information means that we need to be extra vigilant during these months, ensuring that vaccinations are up to date, including older dogs and cats.

5. Prevention is always better than a cure.

Treatment of Parvovirus is difficult, expensive (in the realm of $1,500-$5,000+), and many patients do not survive. Prevention however, is easy, relatively inexpensive, and effective.

Vaccination remains the best way to protect your pet against Parvovirus. Parvovirus vaccination is included in all C3 vaccinations which will also protect your dog against Distemper Virus and Infectious Hepatitis. Most Parvovirus vaccines are considered a 'modified-live' vaccine because they stimulate all aspects of the immune system and induce a longer duration of immunity. They cannot cause disease because the virus is weakened.

Your veterinarian will discuss an appropriate vaccination schedule for your puppy or kitten, as well as how often to present for vaccination boosters. This will ensure a happy, healthy pet in the future - and make sure that those first walks in the park are safe and enjoyable!

Further Reading

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