It is estimated that at least 80% of all the cats in the world are infected with Feline Herpes Virus, which is a major cause of the most severe and widespread respiratory infection in cats, Feline Viral Rhinotracheitis (FVR). Up to 80% of cats who contract FHV-1 remain lifelong carriers of this highly contagious virus and can pass it on to uninfected cats through viral shedding. Reactivation of the virus may occur spontaneously throughout an infected cat's lifetime, although it is often associated with stress.FHV-1 presents a greater threat to kittens, in whom it causes severe respiratory and ocular symptoms. While mortality is generally low in adult cats, it can reach 30% in kittens.In adult cats, FHV-1 flare ups are often hard to differentiate from the other two main feline infectious respiratory diseases, calicivirus and chlamydiosis.Helps lessen the frequency and severity of FHV-1 infections. Enisyl-F is extremely tasty and is easily accepted by most cats.