Of all the infectious diseases in dogs, parvovirus is the one that most owners will have heard of. This serious infection causes severe gastrointestinal signs and can even be fatal for some affected dogs – and there are some reports that it may be becoming more common in the UK. We are going to explore parvovirus in more detail, including what modern treatment options might be available and the practical steps you can take to reduce the risk of a parvovirus outbreak.

What is parvovirus in dogs?

Canine parvovirus (CPV), also known as ‘parvo’, is a virus that causes serious illness in very young and/or unvaccinated dogs. It is a common cause of acute (sudden onset) diarrhoea and vomiting, as well as creating issues elsewhere in the body.

CPV infects and destroys rapidly dividing cells found in the lining of the small intestine, which causes problems with the normal gut barrier function. This allows bacteria to creep through the guts into the dog’s bloodstream, which could lead to septicaemia. The ability of the small intestine to properly absorb nutrients from food is also severely impaired, and there is massive fluid loss.

CPV also affects rapidly dividing cells in the bone marrow and lymph nodes which can reduce white blood cell production. This leads to a weakened immune system meaning that septic shock and organ damage are much more likely to occur. Some very young or unborn puppies are also at risk of serious heart problems. 

How is parvovirus spread?

The virus is shed in the faeces of infected dogs. It can be picked up by direct oral or nasal contact with infected faecal material or by indirectly contacting infected surfaces or objects (e.g. kennel flooring, bedding, owner’s shoes, toys). This makes it highly infectious.

The parvovirus is also extremely resistant to many household cleaning products, as well as to changes in temperature and pH. This means that it can survive for many months, or even years, in the right conditions. 

Infected dogs will start to shed the virus in their stools within 4-5 days after first picking it up, often before any clinical signs develop. 

It’s therefore easy to see how parvovirus outbreaks can occur.

What are the symptoms of parvovirus in dogs?

The classic symptoms of canine parvovirus are –

  • Severe diarrhoea – often watery, haemorrhagic (bloody) and foul-smelling
  • Vomiting
  • Lethargy
  • Pale gums
  • Abdominal pain
  • Reduced appetite
  • Collapse
  • Death

How is parvovirus diagnosed?

The vet will first examine the affected dog to assess their general condition. This will include looking for signs such as dehydration with skin tenting and dry/tacky or pale gums being indicators. The vet will also assess the dog for abdominal pain, check their temperature and look at their demeanour e.g. happy and bright, depressed, or collapsed. 

If the vet needs to confirm parvovirus they may perform a test on the dog’s faeces. Many practices have patient-side tests that can give a rapid positive or negative result. The vet may occasionally send further samples off to the lab for further confirmation.

Blood tests might be recommended to assess for other issues such as anaemia (low red blood cells) or reduced levels of white blood cells, as well as checking for organ damage. 

If the diagnosis is still not clear, then other tests such as ultrasound scans or X-rays may be required to rule out other diseases such as a foreign body or pancreatitis. 

What treatment is available for parvovirus in dogs?

For years, parvovirus treatment has been supportive. There is no cure for parvovirus which means that vets concentrate on correcting the symptoms associated with the disease, as well as preventing problems from getting worse. Sadly, despite the possible best care, some dogs will still die.

Affected dogs will therefore need some or all the following treatments to help them recover –

  • Intravenous fluids – Fluids may need to be given via a drip to correct the dog’s dehydration and to account for any ongoing fluid loss. Abnormal electrolyte levels can also be corrected.
  • Antibiotics – Antibiotics don’t treat the underlying viral infection, but they help to prevent secondary infections which are common in parvovirus
  • Anti-nausea medication – Medication can be given to reduce vomiting in affected dogs
  • Correct nutrition – A highly digestible diet fed little and often can help to support recovery in these dogs. Some may require a feeding tube if they are not taking food voluntarily.
  • Analgesia – Analgesia (pain relief) may be required by some patients.
  • Hospital care – Monitoring by trained professionals is important for recovery. Affected dogs will also need cleaning up regularly and need to be kept warm, as their poor circulation can make their body temperature drop.

Whilst being treated at a veterinary hospital, it is likely that your dog will be kept in isolation. This means that they won’t be allowed to contact other animals and will be barrier-nursed. Staff will wear appropriate protective clothing such as gloves, shoe covers and aprons, to prevent the spread of the virus to other patients.

Modern treatments

Research in the field has been going on behind the scenes though, with some new therapies proving potentially useful in the treatment of parvovirus, alongside the traditional treatments listed above. You will need to speak to your vet about the availability and cost of these medications.

These include –

Monoclonal antibodies

In 2023 a new treatment for parvovirus was approved in the US using monoclonal antibodies. These proteins are formulated in a laboratory and are designed to help the immune system more readily identify infectious agents, meaning they are destroyed. The Canine Parvovirus Monoclonal Antibody binds to the parvovirus stopping it from entering and damaging the intestinal cells. Dogs that are affected with parvovirus can be given a single dose of this treatment, which greatly reduces their clinical signs and can prevent death. This marks a big step forward in the management of parvovirus.

Gelatin tannate

Another new treatment that has shown promise is a drug called ‘Tasectan’ made from tannic acid and gelatin. The tannic acid has antibacterial and anti-inflammatory properties, and when combined with the gelatin, it can create a protective biofilm over areas of inflamed intestinal lining. This prevents fluid losses as well as protecting the intestinal wall from bacterial invasion.

Recombinant interferon omega

Recombinant feline interferon-omega (an anti-viral medication) has shown a reduction in clinical symptoms and death in puppies affected with parvovirus. This drug stimulates the body to produce more antiviral proteins, to help cope with the infection and reduce virus replication. Further research is required to understand how the medication works and to determine the best dosing protocol.

How do we decontaminate the environment after a parvovirus diagnosis?

It can be a difficult task to decontaminate an area affected by parvovirus. Here are some top tips for sanitising and disinfecting –

  • Mechanically clean – Thoroughly remove all faeces and vomit before attempting to disinfect. This is easier on hard surfaces like concrete but can be challenging on grass. Spray outside areas down with water to remove and dilute any material.
  • Sort toys and bedding – Heavily soiled bedding and toys may need to be thrown away. Anything that has been mildly contaminated can be washed on a hot soap/bleach cycle.
  • Wash bowls – Non-porous bowls like metal and ceramic can be washed with an appropriate detergent, rinsed well and then disinfected with at least 10 minutes of contact time. Allow the bowl to dry, before rinsing it with water and allowing it to dry again. Plastic bowls with bite marks or wear and tear should be thrown away, as this makes them porous and hard to properly clean.
  • Bathing – Bathe dogs that were infected and are recovering using their normal dog shampoo. This will dilute the amount of virus particles present in their fur, reducing the risk of transmission. 
  • Choose your disinfectant carefully – Many products claim to kill viruses but not all will work against the hardy parvovirus. 

Bleach (5% sodium hypochlorite) can be effective if used properly at 1 part bleach to 32 parts water. This diluted mixture should be left in contact with the area for 10 minutes before rinsing. Bleach may not be appropriate for all surface types though. 

Potassium peroxymonosulfate disinfectant also has some detergent properties helping when mechanically trying to clean up vomit and faeces. It can be used in carpet cleaners to disinfect carpets and furniture (after spot testing) as well as outdoor surfaces. The area must be soaked for 10 minutes, but it can be left to dry and doesn’t require rinsing.

Accelerated hydrogen peroxide (AHP) disinfectant has detergent properties which means it can be used for helping mechanically clean organic material as well as killing the virus. It should be diluted 1 part AHP to 32 parts water and must have a 10-minute contact time. It can be used in carpet cleaners and sprayed on grassed areas with a pesticide sprayer. No rinsing is required. 

  • A note on cleaning the garden – Cleaning grass areas is difficult. As discussed in earlier points, first dilute the area by spraying it with water, allowing it to dry. Then apply a disinfectant that is effective when organic material is present such as AHP.  There is no 100% guarantee that the area will be completely safe however, so it is best to treat grassy areas at least twice, ensuring the area completely dries out properly between sessions. It is sensible not to let an unvaccinated dog into the garden for 6-12 months after it has been contaminated. 

What preventative measures are there for parvovirus?

Vaccination is a key part of stopping your dog from catching and spreading parvovirus. A primary course of vaccinations is required as a puppy, with regular boosters thereafter. For canine parvovirus, boosters every 3 years usually give adequate protection whereas other diseases like leptospirosis and kennel cough require annual vaccination.

While the parvovirus vaccination can be given to very young puppies (6 weeks), it often needs repeating as they get older due to the interfering effects of antibodies from their mother’s milk (maternally derived antibodies). This is one of the key reasons why vaccination failure might occur. Some breeds are also more susceptible to vaccine failure such as Rottweilers, Staffordshire bull terriers and Dobermanns.

Speak to your vet for the latest guidance about the timings of these vaccinations. 

Summary

Parvovirus is an extremely infectious disease that can be fatal, in young or unvaccinated dogs. Affected animals usually need hospitalisation for intensive monitoring and treatment. However, new therapies are emerging that may help the way that vets treat parvovirus, improving patient outcomes. Following a confirmed case, steps should be taken by owners to decontaminate affected areas and reduce the risk of parvovirus spread to other dogs. Vaccination is the best way to protect your pet against this disease going forward. 

Speak to your vet if you have any concerns about your dog’s health or any questions about vaccination.