Porcine Circovirus Associated Diseases have existed for over 100 years, though Porcine Circovirus type 2 (PCV2) was not discovered to cause disease in swine until the 1990s. In 2004 the outbreak of a new strain severely impacted the pork industry, and led to commercial vaccination. Vaccination changed PCV to endemic and subclinical, but not vaccinating leads to an increase in mortality. As well, PCV is affecting younger pigs, adapting into new strains, and can have long term reproductive and immune functioning impacts.