Summary of Section 3: Epidemiology:  FCoV is a contagious virus. Faeces are the main source of FCoV infection and most transmission is faecal-oral in nature.  Kittens are often infected at a young age and shed FCoV in faeces as early as two days post-infection. After infection, shedding continues for days, weeks or months, and a few may be persistently infected. Shedding then stops, or is detected intermittently, and can recur due to re-infection in an endemic environment. Immunity is short-lived, which is why cats, in the face of infection, can undergo multiple cycles of infections.  FCoV infection occurs worldwide (see Table 1) and is very common, particularly in multi-cat households, but FIP arises in only a small percentage of FCoV-infected cats.  Cats of any breed or age can develop FIP. It is particularly seen in pedigree cats (especially in certain breeds in some studies) and those under 2 years of age. In some studies, males were more likely to develop FIP than females.