Air filtration systems get high marks for keeping porcine
reproductive and respiratory syndrome (PRRS) virus out of farms.
Controlling aerosol spread of PRRS virus seemed nearly
impossible a few years back, before the advent of air filtration
systems for hog barns.  Boar stud expert Darwin Reicks, DVM,
Swine Vet Center at St. Peter, MN, addressing a packed crowd at
the Leman Swine Conference in St. Paul, MN, in mid-September,
provided evidence that the use of air filtration has been a
resounding success.  In 2½ years of experience with various
types of air filtration systems on 15 client farms in hog-dense
areas of south central Minnesota, just three farms have had PRRS
breaks, he reports. Those three breaks occurred during the
summer when the farms were not filtering outside air at all,
relying instead on cool cell systems for ventilation. About 75%
of the filtered farms had a prior history of PRRS breaks.  “We
have not had any PRRS breaks on the sites during 100%
filtration, nor have there been any breaks