Chlamydiosis in Cats

Chlamydiosis is a contagious bacterial infection caused by Chlamydophila felis. This bacteria is responsible for Conjunctivitis, inflammation of the eye or infection of the delicate membranes – conjunctiva. Though Chlamydia is species specific, strains of this bacteria can infect other species. It is also known as Chlamydia psitacci var felis, Feline chlamydophila, Chlamydia psittaci, C. felis, Chlamydophilosis, Chlamydial Conjunctivitis and Chlamydophila felis infection. It was earlier known as Feline Pneumonitis (Pneumonitis is the inflammation of the lungs).

Chlamydiosis is a ZOONOTIC disease, which means humans can easily get affected.

Transmission happens from direct contact with the virus. Once in the body, Chlamydia colonizes and rapidly starts multiplying in the ocular area, respiratory tract, reproductive tract and the gastrointestinal tract. C.felis bacteria needs a host (cat), it cannot survive in the environment. It infects the inner surface of the eyelids or the white part of the eye causing mild to severe swelling. Initial clinical signs resemble an eye infection such as ocular discharges, inflammation/swelling/reddening of one or both eyes, followed by nose and throat symptoms.

Chlamydiosis in often seen in younger cats, kittens with developing immunity, immunocompromized cats with existing diseases causing weakened immunity to fight the infection, cats which have not been vaccinated and senior cats, over 7 years of age with reduced immunity capabilities to ward off the infection.
Boarding homes, catteries, areas with a high cat population and unhygienic environments often have outbreaks of this infection. Chlamydiosis is a bacterial infection and all cats are bound to get infected at-least once in their lifetime. Conjunctivitis cannot be avoided once the bacteria invades the body. is so common that cats will get this infection at-least once in their lifetime.


Feline Chlamydiosis is a bacterial infection caused by the Chlamydophila felis bacteria.
Any direct or indirect contact with the bacteria can cause the infection.

Contaminated materials and objects such as food bowls, bedding, furniture, cat toys or from ocular secretions of an infected pet, catteries, cat populated areas, boarding homes can lead to a cat getting infected.

Clinical Signs and Symptoms

The incubation period for C.felis is between 3 to 10 days. Symptoms can start with Ocular then progress into respiratory.

Ocular (eye) signs
› Recurrent ocular discharges
› Epiphora (Watery eyes)
› Red or pink color eye
› Pain
› Discomfort
› Constant rubbing and scratching of the eye
› Blepharospasm (excessive blinking)
› Discharge becoming thicker and yellowish

Respiratory signs
› Rhinitis (sneezing)
› Recurrent nasal discharges / runny nose
› Coughing
› Lethargy
› Anorexia (Loss of Appetite)
› Tachypnea (Rapid Breathing Rate)
› Dyspnea (Trouble Breathing)
› Pyrexia (Fever)
› Pneumonia
› Dehydration

If left untreated, cats will be infected with conjunctivitis for long period of time (2 months or more), where they will keep shedding the potential source of infection to other cats. Chronic respiratory conditions develop, gradually progressing to Pneumonia which can be life threatening.


Chlamydiosis can be difficult to diagnose as it mimics the symptoms seen in other known diseases. Conjunctivitis is a clinical sign seen in diseases such as Feline viral rhinotracheitis (FVR), Feline Calicivirus (FCV), Keratoconjunctivitis Sicca, Mycoplasmosis, Blepharitis and others.

Veterinarians will require a complete history of your dog which includes medical history, vaccination records, existing health concerns, current and previous medications, onset of symptoms, diet and exercise routine and any information which can help in establishing a correct diagnosis. Diagnosis is done with a combination of tests. These include routine lab examinations and special tests. These are

› Physical examination
› Complete Blood Count (CBC)
› Bacterial culture test
› PCR test (Polymerase Chain Reaction)
› IFA Test (Immunofluorescent assay)
› Antibody test


Treatment of Chlamydiosis depends on the severity of the infection. In 95% of the cases veterinarians will prescribe:
› Topical Eye ointments, creams, eye drops
› Fluid therapy ( in-case of dehydration)
› Dietary changes are suggested
› Medicines and drugs to teat secondary illnesses and diseases

For severe cases, the pet may have to be hospitalized.
› IV Fluids will have to be administered
› Steroid based ointments
› A calmer and peaceful environment to reduce stress

In either cases, Antibiotic medications are also suggested.

Home Care

Chlamydiosis is known to cause eye and respiratory illness. Home care should aim at improving the condition. Treatments can take a few days. Most pets show signs of recovery within 15 days. Treatments can range from a few days upto a month depending on the severity. Post infection, the pet will continue shedding the bacteria for upto 2 weeks. If you observe any behavioral changes, or if the condition does not improve, please contact your veterinarian.

› It is mandatory to provide a stress-free environment for your dog. Keep water and food bowls within reach. Avoid physical activity. Keep your cats away from any noise and commotions.
› You have to administer and monitor all prescribed medicine as directed by your veterinarian.
› Vaccinating your cat (if not done)
› Do NOT travel with your cats.
› Do NOT allow your dog to roam freely. This works two ways, firstly if the pet is infected, it greatly reduces the chances of risk of exposure to other pets and humans and secondly in-case of a healthy pet, it reduces the chances of contracting the infection. Do not allow your pet to go through garbage bins, water sources, fecal infected areas.
› Use of environmental disinfectants is recommended. Prompt disposal of any and all materials after use is suggested.
› A well planned, nutritious diet is necessary in such conditions. Routine and regular checkups to access the progress, further tests may be advised.
› Humans, especially children, pregnant women and pet handlers need to exercise caution. Wear gloves when dealing with a pet, wiping ocular and nasal discharges with damp cloth, cleaning the litter boxes, disposing any and all contaminated materials, garbage disposals etc. A thorough wash of hands is advised. Practice hygiene.

In-spite of a successful treatment and a speedy recovery, there is a high probability this infection can re-occur. Seek veterinarian advise post recovery on ways to prevent this. Always keep in mind untreated Chlamydiosis can progress into life threatening Pneumonia.

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