Feline Calicivirus (FCV) is a contagious virus that primarily affects cats, causing respiratory infections. It is one of the main contributors to feline upper respiratory disease complex, leading to symptoms such as sneezing, nasal congestion, and oral ulcers. The virus spreads through direct contact with infected cats or contaminated surfaces. Vaccination is an effective way to protect against FCV, and it is often included in routine feline vaccinations. While most cats recover from the infection, some may develop chronic issues or complications. Proper hygiene and isolation of infected animals can help prevent the spread of the virus among cats.