Cat Infections – Common Infections in Cats

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  • What is an infection?

    An infection occurs when a disease-causing organism (known as a pathogen) enters the body obtaining nourishment and reproducing and causing harm.

    There are a significant number of infectious agents that can affect cats. They fall into several categories depending on the pathogen (disease-causing microorganism).

    This list by no means includes all infections, just a selection of the most common ones seen in cats.

    An infection can affect any part of the body and in some cases, several. For example, feline herpes can cause eye discharge, nasal discharge, sneezing etc.

    What are the signs of infection in cats?

    Clinical signs will depend on the pathogen. But usually, the symptoms your cat is displaying can give your veterinarian a clue as to possible causes. Not all of the symptoms below mean your cat has an infection; for example, a cat vomiting may be suffering from poisoning or diabetes.

    • Fever (bacterial, viral or fungal)
    • Diarrhea (viral, bacterial, protozoal)
    • Nasal discharge (viral, bacterial, fungal)
    • Vomiting (viral, bacterial, protozoal)
    • Eye discharge (eye infection, cat flu)
    • Weeping skin (bacterial infection)
    • Abscess (bacterial infection)
    • Skin sores (bacterial, fungal)
    • Difficulty urinating (bacterial)
    • Weight loss (viral, bacterial, protozoal, parasitic)

    What are the most common types of infections in cats?

    Upper respiratory infections are a common cause of flu-like infections in cats. There are three main viruses responsible: feline herpesvirus, calicivirus, and chlamydiosis.

    Abscess: Another common type of infection in cats is a bite wound abscess, usually caused by cats fighting. Due to the nature of a cat’s teeth, which are sharp, bacteria are injected under the skin, causing bacteria to form an abscess. Un-desexed cats are especially prone to developing bite wound abscesses due to the fact they are more likely to roam and get involved in fights with other cats.

    Eye infections are common and can be viral, bacterial or fungal.

    Urinary tract infections are a leading cause of litter tray problems (going to the toilet in inappropriate places).

    Parasitic worms: There are several types of worms to infect cats. The most common is roundworm. Cats may not display any symptoms of a worm infection until heavily infected. It is essential to maintain a regular worming schedule for all cats, even indoor ones.

    What is the treatment for infections in cats?

    Treatment will depend on the type of infection, but can include the following:

    Antibiotics are used to treat bacterial infections; they can not treat viral infections, however. In some cases, your veterinarian will perform a bacterial culture and sensitivity to determine the exact type of bacteria involved, and then prescribe the appropriate antibiotic to treat that particular strain.

    Supportive care such as fluid therapy and nutritional support for viral infections.

    Anti-fungal medication and supportive care for fungal infections.

    Can cats infect humans?

    Yes, in some cases, cats can transmit the disease to humans, which is known as zoonoses. Cat bites have an extremely high rate of infections. Other zoonotic diseases include ringworm, toxoplasmosis (which is extremely dangerous if a woman becomes infected during pregnancy) and cat-scratch disease.


    • Julia Wilson, 'Cat World' Founder

      Julia Wilson is the founder of Cat-World, and has researched and written over 1,000 articles about cats. She is a cat expert with over 20 years of experience writing about a wide range of cat topics, with a special interest in cat health, welfare and preventative care. Julia lives in Sydney with her family, four cats and two dogs. Full author bio