A new study conducted by the University of Minnesota provides a clearer understanding of the potential role of noncommercial pigs in the spread of porcine reproductive and respiratory syndrome (PRRS) virus.

In the study, blood was collected for antibody testing by PRRS enzyme-linked immunosorbent assay (ELISA) from 661 pigs at slaughter as well as 32 pigs from which blood samples were collected over time. Serum samples were taken at slaughter, at county fairs and on farms.

Spatial databases of commercial farms and 4-H participation were evaluated with the use of geographic information systems software. The 4-H’ers also provided information about their disease and management knowledge through a mail survey and personal interview.

The researchers found that participation in 4-H swine programs in Minnesota was geographically associated with commercial swine production in the state, and that 39% of 4-H participants raised pigs at locations that had commercial pig production.

There was a high prevalence of PRRS virus antibodies at fairs, averaging 49% and ranging from 29% to 76%. Noteworthy, seroconversion to PRRS occurred after attendance at fairs, indicating that PRRS virus exposure was common in pigs shown by 4-H participants and that transmission of the virus could occur at fairs.

The results of this study highlighting the relative weakness of knowledge of biosecurity practices, evidence of frequent PRRS virus exposure, the tendency for 4-H’ers to show pigs at multiple events and often close interactions with commercial herds suggest that the 4-H community should be involved in regional efforts to control PRRS.