Herpesvirus in Cats

Feline herpesvirus (also called feline rhinotracheitis virus or feline influenza) is one of many upper respiratory infections your cat or kitten may likely experience. Upper respiratory infections are the most common infectious diseases in cats and are easily spread in multi-cat environments. While they rarely cause death in adult cats, they often cause serious illness and death in young kittens. This disease cannot be transmitted from cats to humans.

Herpesvirus in cats causes many respiratory symptoms, but also affects the reproductive system. It is not known whether it is caused by the virus itself or by secondary infections due to viral infections, but abortion is common in pregnant female cats infected with this virus.

Signs & Symptoms of Feline Herpesvirus

Discharge from eyes, nose, or mouth
Inflammation of the nose
Labored breathing
Excessive drooling
Frequent sneezing
High fever that may fluctuate
Conjunctivitis or ulcers in the eyes
Severe lethargy
Anorexia
Abortion in an infected pregnant female

Causes of Feline Herpesvirus

The majority of feline upper respiratory infections are caused by one of two viruses, herpesvirus or calicivirus. Cats may be infected with one or both of these viruses, as well as other bacterial and secondary infections, causing a "feline respiratory disease complex."

Herpesvirus is typically transmitted by direct contact with infected eye, mouth, or nose discharge. Infected dishes, carriers, bedding, litter boxes, and human hands in multi-cat environments, such as kennels and shelters, may also be a route of infection.

This disease typically lasts two to four weeks, but may last up to six weeks in severe cases.

Diagnosis of Feline Herpesvirus

Diagnosis always begins with a complete history and a physical exam. Your veterinarian will most likely recommend some variation of the following:

Physical Exam/History - Your veterinarian may diagnose this disease based on the signs and symptoms your cat is displaying. The inflammation of the eyes along with respiratory symptoms is usually diagnostic of feline herpesvirus. It may be more economical to perform in-house tests for diseases with similar symptoms to rule them out instead of sending samples to a lab.
Immunofluorescence - This is a technique used to illuminate either viruses or their antibodies in a tissue or culture using a fluorescent dye. Proteins labeled with a chemical specific to this disease will be used to detect the antibodies. They will appear under a microscope as a bright green spot on the slide.
Qualitative PCR Test - This "polymerase chain reaction" test is a very specific and sensitive DNA test that can be used to look for an agent in a cat’s DNA. Your veterinarian will obtain a swab of your cat’s throat and send it to a lab to test for the virus. This test may also be used to see if your cat has the chronic form of calicivirus and is shedding the virus after the symptoms have gone away.

Because many cats are carriers of herpesvirus, a positive test result for herpesvirus does not always indicate the cause of the respiratory infection.

Treatment for Feline Herpesvirus

If your veterinarian suspects upper respiratory infection caused by herpesvirus, they will likely do the following:

Isolate your cat in a cage with appropriate humidity and oxygen to ease breathing.
Encourage food and water intake to prevent dehydration and promote a strong cat with a healthy immune system.
Treat signs of dehydration with subcutaneous or intravenous fluids.
Antibiotics may be used in moderate to severe upper respiratory infections to treat or prevent primary or secondary bacterial infections.
Nasal passages may be cleared with nose drops put into alternating nostrils once a day for no more than five days.
Treat ulcers and infections of the eyes with appropriate medication.

Prevention of Feline Herpesvirus

Herpesvirus of cats may be prevented by:

Keeping your cats up-to-date on all of their vaccines - a combination live vaccine for panleukopenia, rhinotracheitis, calicivirus, and other viruses is available. While it does not appear to prevent herpesvirus infection, it can reduce the severity of symptoms and viral shedding if your cat becomes infected. For this vaccine to be effective, it is recommended that cat owners adhere to a strict vaccine schedule.
Admit only vaccinated cats into your multi-cat household and use caution when introducing new cats.
Separate infected cats and unvaccinated kittens and prevent contamination of others by disinfecting hands, bowls, bedding, carriers, etc. with a normal household disinfectant.
Use caution and vaccinate females intended for breeding.
Maintain a stress-free environment to prevent shedding of the virus in chronically infected cats.