Porcine circovirus type 2 (PCV2) is found all over the world in domestic pigs. It was first identified in Western Canada in 1991. PCV2 is associated with a number of disease syndromes termed porcine circovirus diseases (PCVD). Post weaning multi-systemic wasting syndrome (PMWS) is the most economically significant expression of the disease, and it can have a severe impact on nursery and/or grower production. PCV2 can be found in all herds, but not all herds have PMWS. We believe that other factors in addition to the virus are needed to trigger PMWS. Some of these factors include the co-existence of other diseases agents such as PRRS, as well as management or production issues such as overcrowding, mixing, grain molds, and other stresses. Also, we believe that there has been some genetic change in the virus compared to the original virus. The new “strain” of the virus has been identified in herds that have experienced the most significant clinical problems. PMWS generally affects pigs that are around 2 to 4 months old. The common clinical signs are wasting or weight loss, pale or yellowish skin color, labored breathing, and diarrhea. Very commonly, affected pigs will have noticeably enlarged lymph nodes. Most herds have seen individual pigs affected with PMWS. On the other hand, more frequently there are reported cases of “herd breaks” with PMWS where the morbidity (number of affected pigs) can range from 4 to 30%, and the mortality (death loss) can reach as high as 20%. Management of PCV2 and PMWS has been very frustrating. There are no effective treatments for affected pigs. Two vaccines have recently been made available in Canada on an “emergency release basis” so we are hopeful that these will assist in control of the disease. To this point, most of the control strategies have been focused on general management principles that help ensure a healthy pig population and minimize viral shedding. It is difficult for us to tell you what steps to take to prevent PMWS if you have not experienced the disease. All the usual bio-security rules should be adhered to as well as possible to try to prevent introduction of the “new strain” of the virus. Good management principles at farrowing, nursery and finisher stages should be followed to minimize the ability for the virus to express itself clinically.