Carlos Vilalta, DVM, PhD, a post-doctoral associate from the University of Minnesota, spoke to Pig Health Today about the MSHMP.

The MSHMP shows that during that same time period, the number of filtered farms increased from 25 to 150 farms in the MSHMP database. Many of the filtered farms are located in hog-dense regions, Vilalta noted.

As farms in the MSHMP database added filters, the researchers logged the number of PRRS outbreaks before and after. “We were seeing a significant statistical difference” in the number of PRRS outbreaks, Vilalta said.

The air filters installed outside a hog barn are designed to filter out large dust particles. That means viral particles attached to the dust are also prevented from entering, thus preventing disease outbreaks caused by airborne transmission.

Filters plus biosecurity

But filters alone cannot keep PRRS out of a hog barn. “When we’re talking about filtered farms, we have to remember that this is a combination,” Vilalta said. “It’s a package — like filters plus biosecurity…”

“It’s a very large investment,” he continued. “If you want that investment to succeed, then you increase other biosecurity practices like having all the doors closed, and reminding the workers what are the correct practices, etc,” he added.

Filters with strict biosecurity will be a frontline defence for hog farms to protect herds should a foreign animal disease like African swine fever enter the US.

Protection of the US swine herd is a major goal of the Swine Housing Information Center. The center funded Vilalta’s project for the purpose of getting “all the tools ready in case of a foreign animal disease,” he added