title: Vaccination with a Porcine Reproductive and Respiratory Syndrome (PRRS) Modified Live Virus Vaccine Followed by Challenge with PRRS Virus and Porcine Circovirus Type 2 (PCV2) Protects against PRRS but Enhances PCV2 Replication and Pathogenesis Compared to Results for Nonvaccinated Cochallenged Controls.
abstract: Coinfections involving porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2) contribute to a group of disease syndromes known as porcine circovirus-associated disease (PCVAD). Presumably, PRRSV infection enhances PCV2 replication as a result of modulation of host immunity. The purpose of this study was to evaluate PCV2 replication and pathogenesis in pigs vaccinated with a PRRS modified live virus (MLV) vaccine and subsequently challenged with a combination of PRRSV and PCV2. During the early postchallenge period, the number of pigs with PRRSV-associated clinical signs was decreased, and average daily gain (ADG) was increased, in the vaccinated group, demonstrating the protective effect of PRRS vaccination. However, during the later postchallenge period, more pigs in the vaccinated group showed increased PCV2 viremia, decreased ADG, increased PCVAD clinical signs, and increased mortality. In this disease model, the early benefits of PRRSV vaccination were outweighed by the later amplification of PCVAD.
authors.affiliation: Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA mniederwerder@vet.k-state.edu.
authors.forename: Megan C
authors.initials: MC
authors.lastname: Niederwerder
authors.affiliation: Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA.
authors.forename: Bhupinder
authors.initials: B
authors.lastname: Bawa
authors.affiliation: Department of Animal Science, Iowa State University, Ames, Iowa, USA.
authors.forename: Nick V L
authors.initials: NV
authors.lastname: Serão
authors.affiliation: Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA.
authors.forename: Benjamin R
authors.initials: BR
authors.lastname: Trible
authors.affiliation: Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA.
authors.forename: Maureen A
authors.initials: MA
authors.lastname: Kerrigan
authors.affiliation: U.S. Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Beltsville, Maryland, USA.
authors.forename: Joan K
authors.initials: JK
authors.lastname: Lunney
authors.affiliation: Department of Animal Science, Iowa State University, Ames, Iowa, USA.
authors.forename: Jack C M
authors.initials: JC
authors.lastname: Dekkers
authors.affiliation: Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA.
authors.forename: Raymond R R
authors.initials: RR
authors.lastname: Rowland
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D018173:Circoviridae Infections / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D017925:Circovirus / Q000276:immunology / Q000502:physiology*; D060085:Coinfection / Q000662:veterinary / Q000821:virology; D004195:Disease Models, Animal; D019318:Porcine Reproductive and Respiratory Syndrome / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D019316:Porcine respiratory and reproductive syndrome virus / Q000235:genetics / Q000276:immunology*; D034421:Sus scrofa; D013552:Swine; D013553:Swine Diseases / Q000276:immunology / Q000517:prevention & control* / Q000821:virology*; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000276:immunology; D014765:Viral Vaccines / Q000008:administration & dosage / Q000276:immunology*; D014766:Viremia / Q000517:prevention & control / Q000662:veterinary; D014779:Virus Replication
chemical_list: D000914:Antibodies, Viral; D014613:Vaccines, Attenuated; D014765:Viral Vaccines