Chlamydia in Cats

Group of Kittens Looking at Something Just Off Camera

Managing a multi-cat home or running a cat shelter has its own set of challenges. One of these is preventing the spread of infectious diseases from one cat to another. Chlamydia is a very common bacterial infection in cats that can pose a risk for cats living together.

What is Cat Chlamydia

Sometimes called Chlamydial Conjunctivitis, chlamydia in cats is caused by the bacteria Chlamydia felis. It is a bacteria that invades and infects your cat's eyes and is one of the most common causes of conjunctivitis in cats. In fact, C. felis can cause up to 30% of chronic conjunctivitis in cats.

Cats can become infected through direct contact with the bacteria, so any ocular or nasal secretions are considered to be infectious.

Cats living in multicat homes, catteries, or shelters are more at risk of contracting chlamydia. C. felis doesn't survive long in the environment, so shared litterboxes, bowls, and toys, while they should still be properly disinfected, are not as likely to cause transmission.

Although all cats can become infected by C. felis, young cats and kittens are the most susceptible.

Symptoms of Chlamydia in Cats

  • Eye discharge
  • Sneezing
  • Nasal discharge
  • Fever
  • Lethargy
  • Squinting of the eyes

The most common symptoms of chlamydia in cats affects their eyes and their upper respiratory tract.

Typically, the very first sign of infection is watery eye discharge, this can infect one or both eyes. This watery discharge will progress to a thicker, yellow, or even greenish colored discharge.

If your cat becomes infected with C. felis you may also see mild sneezing, nasal discharge, occasional mild fever, occasional lethargy, and swelling or reddening of the conjunctiva. Your cat may also be squinting or holding one or both eyes closed due to pain.

Symptoms usually start a few days after infection and, although primarily affecting the upper respiratory system, if left untreated can spread to the lower respiratory tract and lungs.

Symptoms are usually the most severe a week and a half to two weeks post-exposure. After two to three weeks the symptoms may subside, but some cats may have symptoms that persist.

Diagnosing Chlamydia in Cats

If you suspect your cat to have contracted C. felis you should bring them to the vet. Upon arrival, your vet will perform a physical exam, including a thorough look at your cat's eyes.

They may perform a fluorescein stain to check for a corneal scratch or a Schirmer tear test to assess your cat's tear production. A corneal scratch can also cause an increase in eye discharge and eye squinting. Your cat may develop a corneal scratch or ulcer if they are rubbing their eye because it's painful and accidentally scratch it, but a positive fluorescein stain test is not a hallmark of chlamydial infection. Likewise, if your cat has dry eye their eyes may produce a thicker, yellowish colored discharge instead of normal test.

Your vet may also take swabs of your cat's conjunctiva to examine the cells under the microscope in order to check for signs of infection.

To more definitively diagnose chlamydia in your cat, the vet may also send these swabs out to a lab for a specialized test called a Polymerase Chain Reaction (PCR). This test amplifies the bacteria on the swab in order for the lab to be able to identify it.

Treatment of Cat Chlamydia

If your cat is diagnosed with chlamydia your vet's first choice of treatment will be an oral antibiotic known as doxycycline. If your cat has any known allergy to doxycycline or to other tetracyclines let your vet know and they will prescribe a different antibiotic.

If your cat is in noticeable discomfort, or if the symptoms seem severe enough, your vet may also prescribe an eye ointment or drops to give in conjunction with the oral antibiotics. Your vet may want to treat your cat for several weeks and, if you have other cats, they may also want to treat them for this infectious disease too.

How to Prevent Chlamydia in Cats

There is a vaccine for chlamydia on the market, but it doesn't provide complete protection from the bacteria, so it may not be readily available.

The bacteria C. felis is highly adapted to infecting cats, so the risk of you contracting chlamydia from your cat is low. You should still practice good hygiene after handling a cat with chlamydia or suspected chlamydia, though.

Chlamydia in cats is easily transmitted from cat to cat but also easily treated. If you have questions or concerns about your cat's risk of contracting chlamydia, speak to your veterinarian.