Chlamydia psittaci (Feline Pneumonitis)

Causative Agent: Feline pneumonitis is essentially an upper respiratory infection in cats caused by a specific agent known as Chlamydia psittaci. Chlamydia psittaci is a bacteria-like microscopic organism which cannot live or function outside of the animalís body. Chlamydia psittaci infections commonly occur along with other upper respiratory virus infections such as feline calicivirus and feline viral rhinotracheitis. It usually takes 5-10 days after the initial exposure before clinical signs occur.

Clinical Signs: Chlamydia psittaci infects the tissues of the eye, nose, and lower respiratory tract. The most common symptoms in cats are associated with eye infections. Red, weepy eyes with or without the presence of the third eyelid covering part of the eye (the third eyelid is a fleshy tissue which covers the part of the eye closest to the nose) is the typical appearance of a cat infected with Chlamydia psittaci. Other signs may include sneezing, fever, inappetence, and a clear or colored discharge from the nose.

Disease Transmission and Diagnosis:
This organism is spread by direct contact with infectious material, which can occur through a sneeze or cough. It can also happen when infected hands or equipment come into contact with a susceptible animal. A presumptive diagnosis is usually made based on the clinical signs. To precisely confirm the diagnosis, samples from the involved areas would need to be collected and sent in to a lab for culture and identification.

Treatment: Chlamydia psittaci is responsive to antibiotics. Tetracycline is the antibiotic most commonly used in treatment programs, and it may be given either by mouth and/or as an eye ointment for eye infections. Some animals may require additional support such as fluids and rest, especially if the infection has affected the lower respiratory tract causing pneumonia. These cats may also benefit from a humidifier or being placed in a steam filled bathroom.

Prevention: Like calicivirus and rhinotracheitis, Chlamydia psittaci is a common component in many feline vaccines. An annual vaccination program that is established by a veterinarian and followed by the owner is a key component to prevention. Avoiding stressful situations is always beneficial. Avoiding contact with cats with eye infections or respiratory tract infections will help prevent disease. Outdoor stray or barn cats are commonly infected and frequently are responsible for transmitting disease to other cats which come into their presence.

Public Health Concerns: Chlamydia psittaci has been known to be transmitted to humans from cats with conjunctivitis (eye infections). It is advised to be particularly careful when handling any cat with eye or respiratory infections. Frequent hand washing, especially after applying any treatments into the eye of an infected cat, is highly recommended.