What is Herpes Virus in dogs and how it is fatal for pups?

Learn more about the herpes virus with our handy explainer. 

Herpes or herpes virus is not restricted to human beings alone. Cats as well as dogs and other animals can be infected by this virus. Canine herpes virus (CHV) is also called the ‘fading puppy syndrome’. This virus infects the reproductive organs of older dogs and remains the leading cause of fatalities of the newborn puppies. 

How does a dog contract CHV (canine herpesvirus)?

CHV’s (canine herpesvirus) incubation period is between 6 and 10 days and gets passed on to the puppies through the birth canal. 


If your dog is susceptible and comes into contact with an already infected secretion of other dogs including oral, vaginal, or nasal secretions, CHV is the result. The dogs that do shed the virus show little to no signs of the infection. But, a pregnant female dog may be at high risk of infection and this may then get transmitted to the fetuses or newborn puppies. Therefore, the infection occurs in vitro or in the first three weeks of the pup’s life. As they grow older they develop the required resistance to the infection.

If your pup is susceptible, the CHV gets replicated in the surface cells; this could be in the pharynx, tonsils or the nasal mucosa. The naturally low body temperature in newborns helps accelerate the spreading of the virus and infection. Puppies that have grown past the initial 3 months gradually lose the susceptibility to the CHV. But, until then, extreme caution would be required as the onset is sudden and the illness lasts less than 24 hours before turning fatal.

If your puppies survive this crisis, it is likely that they will still develop a latent infection. Neurological diseases occur and they start to show symptoms by having difficulties in walking or by becoming blind. If the older dog undergoes a stressful phase or if they are prescribed immunosuppressants for any other cause, it could reactivate the latent infection. 

Adult dogs:

In the case of adult dogs, the virus attacks the reproductive tract. This gets sexually transmitted or is transmitted during birth. If the reproductive tract is infected, the disease causes stillbirths and infertility. But, generally the adult dogs more often than not contract the virus through the air as it can spread when an infected dog nearby coughs or sneezes. Drinking water from a contaminated water bowl or sniffing a dog that is shedding the virus are other causes of its transmission.

From time to time, adult dogs that have been previously infected may shed the virus in their vaginal or penile secretions and also, through any nasal discharge. 

Symptoms of herpes virus

Puppies start showing symptoms very early and very quickly. They display difficulty in breathing caused by a respiratory infection; nasal discharge; loss of appetite; seizures; and lesions. Contracting herpes virus also shows as hemorrhage around the blood vessels and you can spot bruising around the belly. 

In older dogs, the upper respiratory infection causes them to cough and sneeze frequently; lesions; conjunctivitis and other infections in the eyes leading to ocular discharge; and ulcers in the cornea are some of the other noticeable symptoms. 

Diagnosis of herpes virus

As the result of CHV in puppies is almost always fatal, a post mortem is necessary to recognize the existence of CHV. This is true of stillborn puppies as well as those that die suddenly. The puppy’s blood gets tested along with tissue samples and swabs of the mucous membranes. This is followed by cell culture studies of the virus from lungs, kidneys, and spleen. 

Treatment of herpes virus

There is no cure or vaccine for herpes virus. There is only symptomatic management or supportive care. For puppies that have not shown any symptoms but are suspected of having contracted the herpes virus, your vet may recommend isolating them and keeping them in a humid and warm environment such as incubators so that the virus is contained. Even if they survive after such treatment, there is likely to have been damage to internal organs including the brain and kidneys. However, injections of antibodies into the abdomen have been tried and this has had some success in keeping the pups alive. 


Is it really possible to prevent the puppies from contracting herpesvirus? Probably not. The best that can be done is isolating the pregnant bitch in the last few weeks of gestation and the first few weeks after delivery. Even if the adult dog shows no overt symptoms of the herpesvirus, shedding of the virus is likely and passing it on to the fetus is unavoidable. Higher risk is when the pup is exposed to it soon after birth and in the first 2-3 weeks. 

Your dog’s handlers need to be extra careful with their protocols to ensure that the puppies remain safe. This is why the use of disinfectants and a stringent cleaning protocol is essential. 

 If the adult dog is already exposed to the virus, she will pass on the antibodies to her litter through the colostrum. So, even if the first litter does not survive, the antibodies may still be able to prevent further fatalities in the future.

Make sure that your adult dog does not show any symptoms such as sores around the vagina or on the penis and if they do, keep them away from breeding. 

Fading puppy syndrome is tragic on many levels. It is tragic to see your puppies fade away before your eyes and the entire process is so sudden that you are left with more questions than answers. You, as the pet parent and your dog’s vet will find this type of fatality beyond your control. The answers may be found only after the postmortem when it is too late. Only saving grace to avoid such deaths would be to try and prevent it from happening with foresight and careful management of pregnant dogs. How successful you are in such prevention is unpredictable.

The information contained in VOSD Vet Advice™ is not intended nor implied to be a substitute for professional medical action which is provided by your vet. You assume full responsibility for how you choose to use this information. For any emergency situation related to a dog’s health, please visit the nearest veterinary clinic.

Do you find this information useful? For more medical advice, visit the VOSD website.