What comes to mind when you hear the term ‘herpes?’ It certainly is a word many of you may associate with the underlying cause of human cold sores…where it often remains dormant (inactive) for many years. But, are you aware that dogs can indeed have herpes?

Many dog breeders will already be familiar with canine herpes virus (CHV) and its associated challenges. Commonly known as ‘fading puppy syndrome’, canine herpes virus can be catastrophic if it hits a breeding household as it is often fatal to puppies. This article will cover the foundations including what canine herpes virus is, which dogs are at risk and how it can be prevented. 

Table of contents

What is canine herpes virus?

Canine herpes virus has been in existence for many years. It is now recognised as one of the most common virulent viral infections in neonatal (newborn) puppies. Canine herpes virus can affect adult dogs, but it has the most severe consequences in very young puppies. Hence why this condition is often familiar to dog breeders. This virus is very talented at hiding in the body’s nerve cells and can reactivate sporadically, usually at times of stress.

How is it transmitted?

Your dog can get canine herpes virus from direct contact with an infected dog via mouth, nose or vaginal fluids. This means that breeding dogs fall into a higher risk category. Transmission of canine herpes virus in puppies is very similar to adults, as it is also transmitted via bodily fluids. If a puppy is born to an infected mother, the virus can be transmitted through vaginal, nose, mouth fluid or even in the womb.

What are the clinical signs?

For many dogs exposed to herpes virus during their lifetime, it never leads to a significant problem. Some adult dogs exposed to herpes virus as a puppy never develop any symptoms if they have a good, strong immune system. But, these dogs are more likely to shed and therefore spread the virus during periods of physiological or emotional stress. Studies have indicated that this virus is carried subclinically (not showing symptoms) by approximately 70% of the dog population (Evermann and Kennedy, 2011).

However, canine herpes virus can cause a variety of symptoms. This adds to the difficulty in recognising this disease. In adult dogs it can cause respiratory disease, as well as eye disease, genital lesions, failure to conceive, abortion and neonatal death. Respiratory disease and neonatal death are the more common manifestations of this virus. Below are the most common clinical signs in adult dogs and puppies:

Adult dogs:

  • Coughing
  • Sneezing
  • Abortion
  • Nasal or vaginal discharge
  • Eye infection
  • Penis or genital inflammation or sores

Puppies:

  • Breathing difficulty
  • Decreased or non-existent suckling
  • Lethargy (tiredness)
  • Nasal discharge
  • Failure to gain weight and poor growth
  • Red spots on their gums (petechiae)
  • Diarrhoea
  • Abdominal pain or discomfort
  • Continuous crying – often a high pitched tone
  • Seizures and neurological signs
  • Death

It may be just one puppy affected or the entire litter.

If you notice any of the above clinical signs, please seek advice from your Vet urgently.

What is ‘fading puppy syndrome?’

Fading puppy syndrome is also known as the ‘fading puppy complex.’ With this condition, puppies are usually born healthy with an ideal body weight, causing no initial concerns at the time of birth. Within the first 14 days, they begin to fail to thrive, lose weight, stop suckling, fade away and often die. Canine herpes virus can be one of the causes of fading puppy syndrome, as well as maternal, congenital, environmental, parasitic and other infectious diseases (Sourabh, 2009). 

How is canine herpes virus diagnosed?

A diagnosis of canine herpes virus is largely made based on the presenting clinical signs and history. A definitive diagnosis can be concluded via post mortem and sampling of deceased puppies. Blood sampling and titre (antibody) testing can also be utilised as a diagnostic tool. 

Can I catch canine herpes virus from my dog?

No! Canine herpesvirus only infects dogs and is species specific. However, its scientific behaviour can be similar to herpesvirus in other species.

Can my dog be vaccinated against canine herpes virus?

Yes! There is now a vaccination available for use in pregnant bitches. The vaccination aims to prevent mortality, clinical signs and lesions resulting from canine herpes virus infections in newborn puppies during their first few days of life (NOAH).

The first injection is usually given either during heat or 7-10 days after mating. The second injection is then given 1-2 weeks before the expected date of whelping. Bitches are revaccinated with the same protocol during each mating.

Once the pregnant bitch is vaccinated, she will pass her immunity onto her unborn puppies to provide protection against the virus during their critical first few weeks. 

If you are a dog breeder and want to enquire about the herpes vaccination, contact your Vet.

What else can I do to prevent transmission?

Prevention of any disease is always better than cure. Alongside the herpes vaccination, there are other sensible measures to take to reduce transmission of this virus. Listed below are a few of these prevention measures:

  • Canine herpes virus is temperature-sensitive and replicates in body temperatures under 37oC. Therefore, it is important to ensure neonate’s temperatures are maintained at an ambient temperature and that the puppies are not exposed to cold or draughty environments. After 3 weeks of age, puppies can better regulate their own body temperature so they are equipped to deter the virus.
  • Always ensure a clean and hygienic environment as the virus is deactivated by disinfectants. 
  • It is also important to isolate newborn and young puppies from adults likely to shed the virus.
  • Ensure the newborn puppies receive adequate colostrum (first milk) from the Mum. This is super important for the transfer of antibodies to strengthen the puppy’s immune system and to also provide adequate energy and nutrition.

If you would like to discuss prevention measures further please contact your Vet.

Is there a treatment for canine herpes virus?

No, there is no treatment or cure for canine herpes virus. Infection is usually lifelong and dogs remain latent carriers. Once dogs are infected, they are infected for life. Treatment is generally supportive and anti-viral therapy may be considered but it is generally unsuccessful.

Conclusion:

To conclude, I hope that the above information has opened up a new thought process when hearing the term ‘herpes.’ From this article, I also hope that you can appreciate the complexity of this virus which I have attempted to summarise in an understandable way! Dog breeders must remain vigilant with canine herpes virus prevention protocols and awareness to minimise the risk of an outbreak and neonatal death in their kennels. With continued and emerging research into infectious diseases, our knowledge into viruses such as the canine herpes virus can only become expansive. 

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