Upper Respiratory Infection (Chlamydia) in Cats

By PetMD Editorial on Jul. 17, 2008

Chlamydiosis in Cats

Chlamydiosis refers to a bacteria based chronic respiratory infection, caused by the Chlamydia psittaci bacterium. Cats that have developed this infection will often exhibit traditional signs of an upper respiratory infection, such as watery eyes, runny nose, and sneezing. With treatment, the prognosis is positive.

Symptoms and Types

Chlamydiosis infection affects the respiratory system, the eyes, the gastrointestinal system and the reproduction systems of animals. Cats experience standard upper respiratory tract symptoms, including: 

  • Sneezing
  • Watery eyes
  • Discharge from eyes
  • Coughing
  • Difficulty breathing
  • Runny nose
  • Lack of appetite (anorexia)
  • Fever
  • Pneumonia, if left untreated


While there is a higher prevalence of this infection in kittens, this condition is present in all ages and breeds. Cats that are kept in crowded quarters with other animals, as in a kennel, are at an increased risk of infection. Added to the risk is the ease with which this bacteria travels. Transmission can take place even without direct contact with an infected animal, as the molecules from a cough or sneeze can travel across a room, a human caretaker can carry the bacteria and spread it by touch, or the cat may come into contact with a contaminated object, such as in a bedding or feeding area.


Your veterinarians will take a sample of the eye discharge, also referred to as a conjunctival scraping or swabbing, in order to have a culture of the fluid done to determine what the source of the illness is. If it is believed that pneumonia is present, an X-ray of your cat's lungs will be performed to check for the presence of fluid.


Treatment is most often performed on an outpatient basis, starting with antibiotics for cats such as tetracycline or doxycycline. Antibiotic treatments may be given orally or as an external direct application onto the eye. The entire treatment process may take up to six weeks.

Living and Management

The cat should be kept away from other animals until the infection heals, since it is communicable; it is also advisable to keep the cat indoors. If there are multiple animals in the household, they should all be treated to prevent another outbreak of the disease.


There is no preventative measure that can be taken for this medical issue, but vaccinations can help to reduce the severity of outbreaks when they do occur.

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