Dog: Herpesvirus

Other common/scientific names: canine herpes

Canine herpes is caused the canine herpesvirus type 1 or CHV1. Herpesviruses are a family of viruses which cause disease in both animals and humans. These viruses have the ability to produce a latent infection meaning the virus can remain dormant in the dog without producing any visible symptoms. Dogs which recover will carry the virus for life. Stress seems to trigger a relapse and increase viral shedding. Puppies are much more prone to developing symptoms of canine herpesvirus than adults. They are most susceptible from three weeks before birth until three weeks after birth.

The incubation period is 3 to 7 days following infection. Canine herpesvirus is spread through direct contact by normal nosing, licking and sniffing between an infected and uninfected dog. It can also be spread by sexual contact. Unborn puppies can acquire the infection from their mother while still in the uterus, during birth or after birth. Dogs which are shown, kenneled frequently or in contact with other dogs are commonly exposed to canine herpesvirus.

• Abortion
• Dying puppies

Most adult dogs show no clinical symptoms. However, mild upper respiratory signs of sneezing, nasal discharge, runny and red eyes may be seen in the adult dog. Even more rare is ulcers of the vagina, prepuce and base of the penis.

Canine herpes is more of a reproductive problem than a respiratory one. Pregnant female dogs exposed to CHV1 can show signs of early embryonic resorption, abortion, still birth or birth of weak, sick puppies.

Puppies which are infected with canine herpesvirus will show signs of shallow breathing, abdominal pain, refusal of food and vomiting. Death can occur within 48 hours of infection.

Blood tests to determine a dog’s antibody levels to canine herpesvirus can aid in the diagnosis. However, some infected dogs will show no antibodies after two months while others maintain an antibody level for years. If the history and clinical signs are suggestive of herpesvirus, then any antibodies found in the blood would be considered significant. Without clinical signs, a positive antibody test only indicates past exposure to the virus not an active infection. A second antibody test can be performed 10-14 days after the initial test. An active infection will show an increase in the antibody level.

Other diagnostic tests include virus isolation from swabs taken of the nasal tract and vagina. This can be performed in the early stages of the infection. A necropsy or postmortem examination of a dead puppy can be performed to aid in diagnosis.

Canine herpes virus is usually fatal for puppies under 3 weeks of age. There is currently no treatment to stop the virus. Serum containing anti-herpes antibodies from a recovered female can be injected into the puppies. Likewise, an antiviral medication can be administered to the pups. However, puppies that do survive often have permanent nervous system and heart damage, so treating infected puppies is not advised.

Adults infected with canine herpesvirus do not need treated. Females which deliver an infected litter may produce enough maternal antibodies to protect future litters.

Prognosis is grave for puppies showing clinical signs. Prognosis is good for adults showing signs of herpesvirus. However, they will always harbor the virus and a relapse is possible.

Any female dog should be isolated from other dogs for the last three weeks of pregnancy and the first three weeks after birth. Maintaining adequate nutrition and housing of newborn puppies can aid in prevention of infection. Since the herpesvirus does not multiply at normal canine temperature, maintaining a pup’s normal temperature can prevent infection.

At dog shows and community areas keep your dog on a short lead and avoid contact with other dogs. If your dog is taken to a kennel, do not share items, food or water between dogs. Keep your dog as isolated from other dogs as possible.

Fortunately, herpesviruses do not live long in the environment and they are easily killed by heat and disinfectants. Spray, wipe down and disinfect kennels before and between animals.

If you have a pregnant female dog, watch her carefully for any signs of illness. If she aborts, gives birth to a dead pup or a pup dies after birth, place the pup in a zip lock bag in the refrigerator and notify your veterinarian immediately. This pup can be submitted for testing.