title: Potential role of noncommercial swine populations in the epidemiology and control of porcine reproductive and respiratory syndrome virus.
abstract: OBJECTIVE
  To assess the role of noncommercial pigs in the epidemiology of porcine reproductive and respiratory syndrome (PRRS) virus.
  
  
  METHODS
  Seroepidemiologic study and survey study.
  
  
  METHODS
  661 pigs from which blood samples were collected at slaughter and 32 pigs from which blood samples were collected longitudinally.
  
  
  METHODS
  Spatial databases of commercial farms and 4-H participation were evaluated by use of commercial geographic information systems software. Information on disease knowledge and management methods of 4-H participants was obtained by mail survey and personal interview. Serum samples for antibody testing by PRRS ELISA were obtained from pigs at slaughter or at county fairs and on farms.
  
  
  RESULTS
  Participation in 4-H swine programs was geographically associated with commercial swine production in Minnesota, and 39% of 4-H participants reared pigs at locations with commercial pigs. High seroprevalence at fairs (49%; range, 29% to 76%) and seroconversion after fairs indicated that PRRS virus exposure was common in pigs shown by 4-H participants and that transmission could occur at fairs.
  
  
  CONCLUSIONS
  The small swine population shown by 4-H members (estimated 12,000 pigs) relative to the population of commercial swine in Minnesota (estimated 6.5 million pigs) suggested the former overall was likely of minor importance to PRRS virus epidemiology at present. However, the relative frailty of knowledge of biosecurity practices, evidence that PRRS virus exposure was frequent, common intentions to show pigs at multiple events, and often close interactions with commercial herds suggested that the 4-H community should be involved in regional efforts to control PRRS.
authors.affiliation: Department of Animal Science and Veterinary Medicine, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN 55108, USA.
authors.forename: Spencer R
authors.initials: SR
authors.lastname: Wayne
authors.forename: Robert B
authors.initials: RB
authors.lastname: Morrison
authors.forename: Carissa A
authors.initials: CA
authors.lastname: Odland
authors.forename: Peter R
authors.initials: PR
authors.lastname: Davies
mesh_terms: D000818:Animals; D003625:Data Collection; D008910:Minnesota / Q000453:epidemiology; D019318:Porcine Reproductive and Respiratory Syndrome / Q000453:epidemiology / Q000517:prevention & control* / Q000821:virology; D019316:Porcine respiratory and reproductive syndrome virus; D016036:Seroepidemiologic Studies; D011795:Surveys and Questionnaires; D013552:Swine