Cat flu, also known as feline upper respiratory infection, is a common illness in cats caused by various viruses and bacteria. The most frequent culprits are the feline herpesvirus and feline calicivirus. Symptoms include sneezing, coughing, nasal discharge, and watery eyes. While it can affect cats of any age, young kittens and unvaccinated cats are particularly vulnerable. Treatment for cat flu typically involves supportive care, such as keeping the cat hydrated and comfortable. In some cases, a veterinarian may prescribe medications to help manage symptoms or treat secondary infections. Vaccination can help prevent severe cases of cat flu and is recommended for all cats, especially those in multi-cat environments.