title: Porcine circovirus-2 and concurrent infections in the field.
abstract: Porcine circovirus-2 (PCV-2) is the necessary cause of post-weaning multisystemic wasting syndrome (PMWS) in swine; however, a variety of co-factors, including other infectious agents, are thought to be necessary in the full expression of disease. Porcine parvovirus (PPV) was found in the inoculum used in the first experiments to reproduce PMWS in gnotobiotic swine. Retrospective and prospective studies in the field and laboratory have demonstrated PCV-2 can act synergistically with PPV to enhance the severity of PMWS. PCV-2 has been shown to play a role in the porcine infectious disease complex (PRDC). Other co-infecting agents with PCV-2 in the lung include, porcine reproductive and respiratory syndrome virus (PRRSV), swine influenza virus (SIV) and Mycoplasma hyopneumoniae. Exposure of pregnant sows to PPV, PRRSV, or encephalomyocarditis virus may interact with PCV-2 infected foetuses. The severity of hepatic lesions in PCV-2 infected pigs may be enhanced by co-infection with agents such as swine hepatitis E virus and Aujezsky's disease virus. Additional studies are required to determine the mechanistic basis for the interaction of PCV-2 with other agents in the pathogenesis of the various clinical syndromes that have been associated with PCV-2 infection.
authors.affiliation: Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Sask, Canada S7N 5B4. john.ellis@usask.ca
authors.forename: J
authors.initials: J
authors.lastname: Ellis
authors.forename: E
authors.initials: E
authors.lastname: Clark
authors.forename: D
authors.initials: D
authors.lastname: Haines
authors.forename: K
authors.initials: K
authors.lastname: West
authors.forename: S
authors.initials: S
authors.lastname: Krakowka
authors.forename: S
authors.initials: S
authors.lastname: Kennedy
authors.forename: G M
authors.initials: GM
authors.lastname: Allan
mesh_terms: D000818:Animals; D018173:Circoviridae Infections / Q000150:complications / Q000276:immunology / Q000662:veterinary*; D017925:Circovirus / Q000254:growth & development* / Q000276:immunology; D009980:Influenza A virus / Q000254:growth & development / Q000276:immunology; D045705:Mycoplasma hyopneumoniae / Q000254:growth & development / Q000276:immunology; D009976:Orthomyxoviridae Infections / Q000150:complications / Q000276:immunology / Q000662:veterinary; D010322:Parvoviridae Infections / Q000150:complications / Q000276:immunology / Q000662:veterinary; D017992:Parvovirus / Q000254:growth & development / Q000276:immunology; D045729:Pneumonia of Swine, Mycoplasmal / Q000276:immunology; D019318:Porcine Reproductive and Respiratory Syndrome / Q000276:immunology; D019316:Porcine respiratory and reproductive syndrome virus / Q000254:growth & development; D013552:Swine; D013553:Swine Diseases / Q000821:virology*; D019282:Wasting Syndrome / Q000150:complications / Q000276:immunology / Q000662:veterinary*