Porcine Parvovirus Infection (PPV) is the most common and important cause of infectious infertility. Porcine parvovirus is a fairly tough virus that multiplies normally in the intestine of the pig without causing clinical signs. It is world-wide in its distribution. If you test for it in your pig herd it is almost certain it will be present unless your herd is less than 100 sows when it might have died out. It is therefore an infection you have to live with and manage. Whereas most viruses do not survive outside the host for any great period of time PPV is unusual in that it can persist outside the pig for many months and it is resistant to most disinfectants. This perhaps explains why it is so widespread and so difficult to remove from the pig environment.