Is Cat Chlamydia Contagious Between Cats?

Chlamydial infections often affect young cats living in multi-cat households.
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Chlamydia is one of several upper-respiratory diseases affecting cats. It is caused by a bacteria called Chlamydophila felis, which is contagious between cats. Once known as chlamydia psittaci or feline pneumonitis, chlamydia has been identified in cats worldwide. Though it's rare, feline chlamydia infections can potentially transfer to humans.

Chlamydophila Felis Defined

Chlamydophila felis is considered bacteria, but is different from other bacteria in that it lives inside cells. Inactive chlamydia, called an elementary body, is picked up by a cat during close contact with an infected cat. Once inside the cells, the chlamydia elementary body transforms into a reticulate body and multiplies. These cellular inclusion bodies can be detected microscopically in tissue samples from infected cats.


The mode of transmission between cats is uncertain, but it is thought to be dependent on close contact. Social interactions during grooming probably spreads the infection. Contagious secretions from the eyes and nose likely infect cats living in close-knit groups. According to the Institute for International Cooperation in Animal Biologics at Iowa State University, recent research suggests that chlamydia infections may spread by venereal transmission, which means during breeding via external sex organ contact.


Usually, this contagious disease presents signs of conjunctivitis and rhinitis, defined as the swelling of the eye and nose membranes of your cat. Tissue areas around your cat's eyes will become red and swollen with possible drainage occurring. Often, chlamydia infections begin in one eye and moves into both eyes. Symptoms will appear three to ten days after exposure to an infected cat and subside over two to three weeks.


Some cats may develop secondary complications during chlamydia infections. Since your cat's immune system is compromised by chlamydia, bacterial and fungal organisms may become opportunistic invaders. Ulcerations may develop on the surface of your cat's eyes, which causes healing blood vessels to invade the surface. Rarely, lungs may develop pneumonia or pregnant females may abort.

Diagnosis, Prevention and Treatment

Diagnosis of chlamydia can be done microscopically by your veterinarian using surface tissue scraping. The scraping may be uncomfortable for your cat but not painful. After a positive diagnosis, sick cats should be isolated from other cats to prevent the spread of chlamydia between cats. Wash your hands after handling infected cats. Feline chlamydial vaccine does not totally protect cats, but it can reduce severity of an infection. Often, both eye antibiotic ointment and oral antibiotics will be prescribed to treat chlamydia infections. Chlamydophila felis is a very treatable disease with low recurrence rates.

Always check with your veterinarian before changing your pet’s diet, medication, or physical activity routines. This information is not a substitute for a vet’s opinion.

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