The two-county PRRS regional control project in Michigan involves Allegan and Ottawa counties, which border Lake Michigan and provide a good natural barrier to disease spread, says Barbara Straw, DVM, project coordinator, Michigan State University.

Program participation has benefitted from the fact that the largest pork producer in the area has agreed to voluntarily share data on PRRS status.

“Veterinarians and producers are willing to work together on this project,” Straw comments. “It is a producer-driven program, and producers are ‘gung ho’ to get it done.”

In all, there are 125 hog sites in the two counties and more than half of the sow sites are PRRS-positive. “Many positive sow herds have implemented a control and eradication program and are currently enjoying a lot of success in producing PRRS-negative weaned pigs,” Straw says.

Many finishing sites also seem to be experiencing a low level of virus circulation.

Straw says there appears to be many different PRRS viruses swirling around the region, but most farm pig flows are dealing with a single strain.

Many farms in the project area are still positive but stable for the PRRS virus.

Samples taken from feral pigs trapped in Michigan were all negative for PRRS, she says.