Diagnosing Feline Herpes Virus with PCR

Feline herpes, also known as feline rhinotracheitis virus, causes feline herpes virus infection, an acute respiratory infection in cats. This is a highly infectious disease that affects both domestic and wild cats. Once a cat is infected, it carries the virus for life. However, since it’s not a fatal disease, it can be managed with medication. Feline herpes may infect cats of all breeds, genders and ages. However, some pets are more susceptible to the infection.

Pets Highly Susceptible to Feline Herpes Virus:

  • Kittens, especially those born of infected mothers
  • Pregnant cats
  • Lactating cats
  • Unvaccinated cats
  • Sick cats
  • Cats living in catteries or boarding facilities

Spread of Feline Herpes Virus Infection

The disease is usually transmitted through contact with fluids secreted from the mouth, eyes or nose of sick cats, or through contact with anything contaminated by such fluids. It’s therefore important to isolate infected cats and wash hands thoroughly after coming in contact with an unknown cat.

Symptoms of Feline Herpes Virus Include:

  • Sneezing
  • Coughing
  • Rhinitis
  • Conjunctivitis
  • Discharge from the eyes and the nose
  • Ulcers in the eye
  • Loss of appetite
  • Fever


Feline herpes virus is difficult to diagnose, as the symptoms are similar to those of other feline respiratory diseases such as feline calicivirus and chlamydia psittaci. In addition, the virus can remain latent (inactive) in an infected cat for long periods, making detection of the disease almost impossible. Although diagnosis of this infection is usually symptomatic, the generic symptoms of feline herpes make diagnosis complex. Definitive diagnosis can be done by direct immunofluorescence or virus isolation tests. The disadvantages are low antibody titres in convalescent cats or latent carriers, and the turnaround time required to reach a diagnosis.

Detection of Feline Herpes by Polymerase Chain Reaction (PCR)

PCR has proved to be very effective in the diagnosis of feline herpes. It helps to detect the thymidine kinase gene in the viral genome. This technique is highly sensitive, rapid, non-invasive and very specific. Specimens are taken from the nasal and conjunctival fluids of the infected cat to conduct the PCR test. A positive PCR test result confirms active infection. The improved rate of detection of the infection makes PCR a preferred test for diagnosis of feline herpes. If there’s an incidence of recurring or chronic infection and if other causes of conjunctivitis or keratitis have been eliminated, a positive PCR result may help the vet diagnose and treat the cat effectively.


A nutritious diet, stress-free living conditions, isolation of sick cats and avoidance of exposure to sick or strange cats are some ways to prevent feline herpes. An annual upper respiratory vaccine protects cats against the infection to a certain degree and if infection does occur in a vaccinated cat, the symptoms are less severe than those exhibited by unvaccinated pets.

It’s important to ensure sanitary and hygienic conditions to safeguard your pet from contagious diseases. It’s also best to seek prompt vet care if you suspect that your pet has contracted a respiratory infection.