What do you think of when you hear the word chlamydia? Most people immediately think about sexually transmitted infections, which spread from person to person through unprotected sex. So, if your vet mentions your cat has chlamydia, it’s only natural you might have a few questions! First things first – there are many species of chlamydia bacteria, so chlamydial infections in cats are different to the one commonly seen in people. We’ll explore this in more detail in this blog.

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What is chlamydia infection in cats?

Chlamydia felis is a very common infectious agent found in cats. It can be caught at any age, but it is most common in young kittens or in environments where multiple cats are kept in close proximity to each other. This bacterial infection commonly causes conjunctivitis and upper respiratory tract infections. The following symptoms might be seen in an infected cat –

  • Sore, irritated eyes
  • Discharge from one or both eyes
  • Swollen eyelids
  • Holding the eyes partially closed
  • The cat may excessively rub their eyes
  • Sneezing
  • Discharge from one or both nostrils
  • Reduced appetite
  • Lethargy
  • Fever

If your cat is showing any of these symptoms, then make an appointment to see your vet.

How did my cat get this infection?

As mentioned earlier, the bacteria Chlamydia felis (previously known as Chlamydophila) causes upper respiratory tract infections. Illness is spread through the transmission of infected nasal or eye secretions and can occur either by sneezing or direct contact (such as mutual grooming). Bacteria shed on food bowls or toys possibly contribute to the spread of disease, but this is less common.

This explains how infection can rapidly spread through catteries or breeding colonies where there are large numbers of cats living in close proximity. Though cats of any age can catch it, kittens are more susceptible as their immune systems are less well-developed.

We do not currently routinely vaccinate pet cats against this illness, as the illness is not usually fatal and can be treated successfully in many cases. However, a vaccine is available which may be useful in some of the high-risk scenarios discussed or where there are ongoing issues with persistent infection.

How is this infection treated?

There are many different reasons cats get conjunctivitis, so your vet may wish to confirm the cause of the infection by taking samples. Swabs taken from around the eyes can be sent to the lab to identify which organism is causing your cat’s symptoms.

If chlamydia is identified then oral antibiotics can be used to treat this infection. Treatment courses typically last 4 weeks (or possibly longer) and some cats may also benefit from topical eye drops. Anti-inflammatories can be helpful in some cases too, as these act as pain relief, reduce a raised body temperature, and help with swelling around the eyes.

If left untreated the infected cat can shed bacteria for many months and have persistent ongoing conjunctivitis.

Some cats may be asymptomatic carriers of the infection, so it is likely that if you have one confirmed case that all cats in the household will need treatment. This is regardless of whether or not they are showing symptoms. Otherwise, it can be very hard to eradicate the infection from the environment.

Can I catch chlamydia from my cat?

Yes, although it is rare. Different species of chlamydia tend to favour different animals, with Chlamydia felis preferring to spread from cat to cat. There have only been a couple of reported cases of humans catching this infection and getting conjunctivitis, so the risk of catching it is low. However, some sources suggest that people may contract it asymptomatically, which goes unreported. Either way, you shouldn’t be unduly concerned as long as you maintain good hygiene measures. These include washing your hands after handling your cat and avoiding close face-to-face contact while they are unwell.

Risks are thought to be higher for people that are immunocompromised or who work in very close contact with stray cats in a shelter or cattery. Speak to your doctor if you have any concerns about your health.

Summary

Chlamydia is a common bacterial infection in cats, causing conjunctivitis and upper respiratory signs. While it is possible for people to become infected, the risk is very low, and can usually be avoided through good hygiene measures. If you have concerns about your cat’s health, then contact your vet for advice. Alternatively, if you are worried about your own health, then speak to your GP as soon as possible.

Thanks to Jacob who asked our editor the question in the first place! – Ed.

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