What is Feline Respiratory Disease Complex?

Feline Respiratory Disease Complex is very common among cats, particularly those that are immunocompromised or unvaccinated. This disease is highly contagious and can spread rapidly in shelter environments or in multi-cat households. Although it is typically self-limiting, disease progression can occur and lead to pneumonia in some cases.

What is it?

Feline Respiratory Disease Complex refers to several viruses and bacteria that cause upper respiratory infections. These include herpesvirus, calicivirus, mycoplasma, chlamydophila, and bordetella. Although the majority of feline upper respiratory infections are caused by viruses, secondary bacterial infections commonly worsen clinical signs. The disease is spread via droplets in the air or close contact with contagious cats.

What are the clinical signs?

The most common clinical signs include sneezing, coughing, nasal discharge, and conjunctivitis.  Eye discharge can range from serous to thick in consistency. Thicker, white discharge usually indicates a bacterial cause, whereas serous discharge is more common with viruses. In some cases, mouth lesions are seen depending on the causative agent. If the disease is chronic or has progressed to pneumonia, respiratory changes and a fever may be present.

How is it diagnosed?

Usually the disease is diagnosed based on clinical signs consistent with an upper respiratory infection. However, virus isolation and bacterial culture may be done to determine the exact cause to better target treatment in non-resolving cases.

How is it treated?

Treatment depends on severity of disease. Even if a viral agent is suspected, antibiotics to protect against secondary bacterial infections are often prescribed. Eye ointment or artificial tears may also be given by your pet’s veterinarian. In severe or chronic cases, cats may need to have subcutaneous fluids administered to counteract dehydration. It may take up to two weeks for clinical signs to fully resolve. Your pet’s veterinarian can provide the most appropriate treatment recommendations.

Cats infected with herpesvirus and calicivirus will have latent lifelong infections. If the cat becomes immunocompromised or stressed, they may begin shedding the virus and become contagious to other cats. They may also have recurrence of clinical signs throughout their lives during times of stress.

Is it preventable?

A core vaccine for cats called FVRCP is the best protection against upper respiratory disease. FVRCP protects against Feline Viral Rhinotracheitis, Calicivirus, and Panleukopenia. Feline Viral Rhinotracheitis is actually caused by herpesvirus as mentioned above. Although cats who have received this vaccine are still susceptible to infection, the risk is greatly minimized. If a cat who has been previously vaccinated comes into contact with these causative agents, the respiratory infection is not nearly as severe and does not last as long compared to unvaccinated cats.