First report of postweaning multisystemic wasting syndrome in pigs in Poland

The present study describes first clinically detected and confirmed by laboratory methods case of PMWS in Poland. The investigation was carried out in a large farrow-to-finish farm producing 40 000 fatteners per year. In the spring of 2000, growth retardation, wasting and respiratory disorders affected 20% of weaners and 30% of fatteners. Nineteen weaners and 11 fatteners with different degrees of wasting, respiratory disorders, skin paleness and hemorrhagic skin lesions (fatteners only) were necropsied. Post-mortem examination revealed the presence of inflammatory signs in lymphoid tissues, enlarged lymph nodes, non-collapsed lungs, enlarged livers, enlarged and pale kidneys with generalized cortical petechiae. Sections of lymph nodes were submitted for histopathological examination and in situ hybridization. Moreover, virus isolation in PK15 cell line was attempted. Histopathological analysis of lymph nodes revealed different degrees of lymphatic depletion and histiocitic infiltrations, giant cells and intracytoplasmic inclusion bodies. In situ hybridization with the use of a specific for PCV2 digoxigenin labelled DNA probe confirmed the abundant presence of PCV2 DNA within lesions in lymph nodes. A peroxidase assay indicated PCV2 replication in the inoculated cell line. Gross and histopathological lesions and the presence of PCV2 antigens in lymphoid tissues confirmed the presence of PMWS in a Polish swine herd. Clinical signs and laboratory examinations indicated that PDNS and PMWS coexisted in the herd. This suggests that PCV2 could be an important factor in an aetiology of PDNS.