The virus
The problem
Treatment
Prevention

The virus

Canine herpesvirus (CHV-1) is a virus that has been largely ignored for many years. However, it is becoming increasingly clear that the virus causes many more problems than was first thought. Like all herpes viruses, CHV is highly infectious, and a recent study showed that more than 80% of dogs in England have been exposed to the virus at some time in their lives.

The problem

For most dogs CHV is not thought to cause any significant problem and so for a long time is has largely been ignored by both breeders and vets. However, it is now clear that CHV can be a significant cause of death in young puppies, and also smaller litter size and weight.

The unborn puppy

CHV attacks the placenta of the mother, starving the foetus of nutrients. This can lead to abortion, stillbirth or re-absorption of the foetus (seen by the breeder as infertility).

The newborn puppy

If the puppy is infected before birth and survives, it may be underweight at birth and have a weakened immune system, making it vulnerable to early puppyhood infections. If the puppy is infected soon after birth, CHV is known to be one of the factors in "fading puppy syndrome", in which the pup fails to suckle, loses weight and fades away despite intensive care.

The adult dog

in the dog, CHV can cause painful lesions on the genitals. In the bitch, there may not be any external signs, but the bitch seems infertile or gives birth to undersize and weak litters. In both males and females, CHV is also known to be a cause of kennel cough.

Treatment

There is no cure for an animal that has CHV - infection is probably lifelong and can flare up repeatedly during periods of stress. Antiviral drugs do not appear to be effective and are very expensive.

Prevention

A new vaccine has just been launched in the UK by Merial Animal Health Ltd, best known as the makers of Frontline®. The vaccine, Eurican® Herpes 205, cannot prevent infection but if given during pregnancy it has been shown to significantly improve fertility rates and reduce early puppy death. Even bitches that already have the virus can be vaccinated.