The illness commonly (and incorrectly) referred to as “cat flu” is most often caused by a virus such as feline herpes virus (FHV-1) or feline calicivirus (FCV), or by the bacteria Bordetella bronchiseptica (BB) or Chlamydophilia felis (feline chlamydia). FHV-1 and FCV are considered “core vaccines” in cats, meaning that every cat should be vaccinated. However, like human cold viruses, they are highly contagious and always mutating. This means vaccination does not give 100% protection, however vaccinated cats tend to experience less severe clinical signs and usually don’t require veterinary intervention (sneezing and watery eyes are the most common signs).
Cats which are immuno-compromised, for example if they have FIV, often experience more severe signs of cat flu. If your cat has a pre-existing condition that reduces their immunity, contact your vet as soon as you notice they are unwell. In addition, vaccination of these cats might not be advised by your vet.
Supportive care you can provide for your cat at home addresses common signs such as blocked nose, congestion, runny eyes, mouth ulceration and lack of appetite:
- Gently clean discharge from the eyes and nose (if your cat allows you)
- If your cat is not grooming themselves, and they allow it, gently wash their face with cotton balls and tepid water. Cats can become very distressed if they can’t clean themselves
- Offer soft/blended, tasty food which has been warmed to increase the smell
- Bring your cat into the bathroom while you shower; the build-up of steam can help their breathing
- Use a nebuliser (if tolerated by your cat; ask your vet professional for guidance first)
- Ensure there is a supply of fresh drinking water at all times
- Minimise stress in your home, and don’t underestimate the value of TLC
If your cat stops eating or appears depressed, lethargic or is having trouble breathing, veterinary attention is needed. Don’t wait days before making an appointment! Cats which stop eating, for example from inability to smell or from mouth ulceration due to FCV, can develop severe complications very quickly. Obvious breathing difficulty should be addressed immediately; a secondary bacterial infection such as pneumonia is serious and usually warrants hospitalisation.
For more severely affected cats, your veterinarian might provide the following treatments (in hospital or at home) depending on the cat’s individual needs:
- Intravenous (IV) fluids to prevent dehydration and maintain electrolyte balance
- Antibiotics, if bacterial infection is diagnosed or if secondary bacterial infection is a risk
- Medications to treat eye disease caused by FHV-1
- Pain relief, if the cat has mouth ulceration from FCV
- Antiviral medication is sometimes prescribed, with variable benefit
- Appetite stimulants, if the cat is anorexic
- A mucolytic powder, such as Bisolvon, is sometimes used in respiratory disease where mucus is present
- Oxygen supplementation, if pneumonia develops
- An oesophagostamy feeding tube might be placed to maintain nutrition in cats which remain anorexic for 3 days, in spite of above-mentioned attempts to encourage eating
Remember that none of these treatments will cure cat flu; the aim is to treat the presenting clinical signs and prevent complications with supportive care, with the aim of getting your cat back on their paws as soon as possible!
In the past, veterinarians commonly prescribed lysine for cats suffering from FHV-1, a theory based on the use of lysine in humans. However, recent studies have found lysine to be of no benefit in cats with FHV-1, and can actually make FHV-1 infections worse.
Finally, avoid giving your cat over-the-counter vitamins, or other medications, unless advised by your vet professional. These are usually of little/no benefit in reducing the severity or duration of illness, unless an actual deficiency has been diagnosed. Take care also with eucalyptus products, as eucalyptus is toxic to cats.
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