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United Kingdom

Feline chlamydiosis

cat on hind legs in blue studio



The classic symptom is a persistent conjunctivitis. This is an inflammation of the pink lining of the eyelids and transparent covering of the eyeball. The eyes can become reddened, and the discharge may be anything from watery to thick and pus-like. It commonly starts in one eye only, before spreading.

Weeks and months later, the cat may still have a dark sticky discharge around the eyes, especially by the tear ducts, needing regular removal. It may cause serious problems for short-nosed and long-haired cats. Symptoms that are more commonly seen at the start of the disease include: Sneezing and nasal discharges, fever and loss of appetite. Symptoms are always worse if the cat has concurrent cat flu


Feline chlamydiosis is an infection of the eyes caused by the bacterium Chlamydophila felis (formerly Chlamydia psittaci). It is a disease that affects cats worldwide. Humans can be infected with chlamydia but Chlamydophila felis is very highly adapted to cats and human infection following contact with an infected cat has been reported on extremely rare occasions.

The Chlamydophila bacterium is readily transmitted from cat to cat. All ages of cats can be infected but disease is seen most commonly in young kittens (5 - 12 weeks of age) and cats in a community such as breeding catteries and rescue centres.

The bacterium typically causes persistent low grade conjunctivitis (inflammation of the lining of the eyes and eyelids). The nose may also be involved causing sneezing and nasal discharge and more rarely the lungs may be involved. Up to 30% of cases of conjunctivitis in cats may be caused by Chlamydophila felis.

Death from chlamydiosis alone is rare. It is the persistent nature of this disease, especially in multi-cat households, that make this disease such a problem. The bacterium is readily killed by common disinfectants, and does not survive long in the environment. Infection occurs by direct contact with an infected cat.


Symptoms cannot be reliably distinguished from other causes of conjunctivitis. Your veterinary surgeon may suspect chlamydiosis where conjunctivitis is the predominant symptom, especially in a multi-cat family, breeder catteries or a rescue centre.


Cats will often need a prolonged course of a specific antibiotic. Topical treatments may also be required, depending on the case. Good nursing care to remove ocular discharges and encouragement to eat will speed recovery.


Prevention of disease may be achieved by vaccination. However the vaccine will not prevent infection in every case but can reduce the severity of the disease. Vaccination is considered more important for multi-cat households which have a problem. Therefore discuss your requirements carefully with your veterinary surgeon. Your veterinary surgeon will advise you on the most appropriate vaccination schedule




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