Canine Herpes Virus Infection in Dogs

While CHV is most common in very young puppies, older puppies and adults can contract the virus and survive. Adults can recover without treatment, although they often become lifelong carriers of the virus and are able to infect other dogs. Close contact is required for transmission, as the virus is unstable outside the host. This includes licking, nosing and the spread of infected fluids, as well as the transmission from mother to fetus. Stress and illness can cause a reoccurrence of CHV in previously infected dogs.

The Canine Herpes Virus (CHV) causes a viral infection in puppies and adult dogs, coyotes and wolves. This infection is systemic, most commonly causing upper respiratory infections, lesions that are visible and internal, and genital infections. CHV is most dangerous for in utero and newborn puppies, usually causing death within 48 hours after symptoms appear.

Symptoms can vary depending on the age of the infected canine.

In puppies, symptoms include:

• Thick nasal discharge, sometimes bloody
• Upper respiratory infections
• Loss of appetite, or a decrease in suckling
• Loss of body weight
• Shallow breathing
• Vomiting
• Lethargy
• Diarrhea
• Pink eye
• Eye lesions
• Corneal edema, or swelling
• Encephalitis, or brain inflammation
• Dull or depressed behavior
• Constant crying
• Restlessness
• Abdominal pain
• Shivering
• Soft, odorless stools that are grayish yellow or green
• Oral or genital vesicle
• Skin redness or rash
• Neurological issues
• Blindness
• Absence of a fever
• Seizures
• Loss of consciousness
• Sudden death

Adult dogs show different symptoms that can include:

• Upper respiratory infections
• Genital infections, such as vaginal or foreskin inflammations
• Eye disease, such as conjunctivitis and dendritic corneal ulcers
• Visible lesions
• Abortion or stillborn litters in females

The cause of canine herpesvirus infection is exposure to the virus. Transmission is from contact with an infected dog by means of:

• Oral secretions
• Nasal secretions
• Genital secretions
• From infected mother to fetus, or to her newborn puppies

Dogs that are more susceptible are:

• Pregnant dogs
• Puppies under 3 weeks of age
• Dogs with compromised immune systems

Diagnosis is often presumed based on a physical examination, the symptoms present, and medical history. Diagnosis and treatment are both dependent on the age of your dog. Blood tests and microscopic examinations can be used to differentiate this infection from other similar ones, and a PCR test on fresh tissue and fluids can be used to detect herpesvirus DNA.

Death occurs in many infected in utero puppies, or puppies between 1 to 3 weeks of age. Cultures collected in post-mortem tests can confirm the presence of CHV, and that diagnosis can alert you to the possible infection of the other littermates and the mother. Lesions can be seen on organs, and the lymph nodes are often enlarged.

Treatment of a canine herpesvirus infection can vary depending on the age of your dog.

In puppies, treatment is often unsuccessful. Many infected puppies die before treatment is sought. If infected puppies are diagnosed before a fatality occurs, then a few steps can be taken.

Antiviral medicines, such as acyclovir, may be beneficial, but unfortunately are often ineffective. An antibody serum from the blood of recovered females may be helpful in reducing deaths in puppies if given before the onset of symptoms. A litter can also be switched to a different female to nurse, one who has been previously infected and tests seropositive for the virus. Keeping the puppies warmed can help, as the virus can’t survive at body temperature. This can be done in incubators. Good hygiene can also reduce puppy deaths.

Prognosis for puppies who survive is guarded due to the damage to internal organs, and they often display persistent neurological issues, such as loss of body control, imbalance, and blindness.

In infected adult dogs, the duration of symptoms is generally short lived, and they often recover without treatment. However, the infection can remain hidden. Recovered adult dogs often become carriers, and can infect others throughout their life. Antiviral drugs may be prescribed. Currently, no vaccine is available in the U.S. or Canada. A vaccine available in Europe has had mixed results.

In puppies, death is generally the result of infection. Puppies infected after 3 weeks of age can show mild symptoms and may recover, possibly with neurological damage. Recovery is good for adult dogs, although they often become lifelong carriers of the virus. The disease can reoccur during stressful times. Recovered females can have future infected or healthy litters, and can also have failed pregnancies.

Prevent infection by avoiding contact with infected puppies and dogs. For pregnant females, ensure she does not get infected in the most dangerous time for her puppies by keeping her away from other dogs 3 weeks before and after giving birth.