Vet at FirstVet answers:
Cat flu is a term used to describe different types of viral and bacterial infections in cats. Cat flu is very contagious and if you have more than one cat at home with symptoms, most of the others are likely to be infected.
Common symptoms of cat flu are sneezing and runny eyes. Fatigue and inappetence can also be seen. Often you can help your cat at home by offering extra palatable food and by removing any discharge from the nose and eyes. It is very important to remove discharge around the nose to make it easier for your cat to breathe.
If your cat is sneezing blood, is very tired and does not want to eat, or if the sneezing and runny eyes do not improve within a week it is best to consult a veterinarian. Likewise if the symptoms return.
Avoid letting your cat interact with other cats while it is unwell. ALWAYS inform your veterinarian when booking an appointment if it has symptoms of cat flu. This is to ensure your cat does not infect other cats by keeping it away from the waiting room.