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Bulletin No. 16 - Fall 2003
Fourth International Symposium on Emerging and Re-emerging Pig diseasesPMWS-PCV2-PCVD-PDNS
KRAKOWKA S, ELLIS JA, MAC NEILLY F, MEEHAN B, RINGS DM, MAC CULLOUGH K, B?TNER A, NAUWYNCK H, CHARREYRE C, ALLAN G
The pathogenesis of PCV-2-associated postweaning multisystemic wasting syndrome in swine.
Proceedings of the 4th International Symposium on Emerging and Re-emerging Pig Diseases, 2003, 143-148
Much work has been done and remains to be done on postweaning multisystemic wasting syndrome (PMWS) and its, now recognized as such, necessary causal agent porcine circovirus type 2 (PCV2). Prior to the first reported outbreaks of PMWS in 1991, PCV2 infection was already occurring, but such a sporadic infection has mysteriously changed into an epidemic disease. This brief review presents the states of the art regarding PMWS and PCV2 with references to experimental reproduction of the subclinical infection and PMWS in gnotobiotic swine by oral inoculation. The monocyte-dendritic cell-macrophage lineages are known to harbor infectious material and are a key feature of the disease. However the primary cellular tropism of PCV2 as primary site of replication still needs to be identified. Gut epithelia, hepatocytes, vascular endothelia, K?pffer cells and histiocytes-like cells have been studied as early virus-permissive cells and represent a lead to further investigate. A dose-effect correlation is on the way to be demonstrated between amounts of PCV2 in tissues and clinical expression of the disease. Another unknown factor is still the link between immunostimulation (early vaccinations) or immunosuppression (cyclosporine) and the genesis of the disease.
