Porcine circovirus type 2 (PCV2) is a common virus present in most parts of the world. PCV2 has been pointed out as the major causative agent to post weaning multisystemic wasting syndrome (PMWS) that affects pigs after weaning. The clinical symptoms of PMWS are impaired growth, diarrhoea, respiratory problems and increased mortality. At autopsy enlarged lymph nodes with depletion of lymphocytes are commonly found. Since 1991 PMWS has spread all over the world and was first described among Swedish pigs in 2003. Although PCV2 is widespread, only some pigs develop PCV2-related diseases. Why this is and what other factors that are required in order for the disease to develop is yet unknown. The main theories involve other infections, for example PRRS, and management issues but also genetic differences between pigs and/or virus strains have been suggested.

A couple of hundred years ago half of the earth?s surface was covered by forest. Today, only half remains and every year an area the size of Nepal is disappearing. Deforestation, together with the burning of fossil fuels, is also one of the reasons for the increasing greenhouse effect. Another relatively unknown problem for the world?s forests is the trade with illegally harvested timber.