Wisconsin recently depopulated two commercial swineherds that had contracted the pseudorabies virus.
The last case of pseudorabies in a U.S. commercial herd occurred in early 2003. Routine surveillance at slaughter found the virus in a Wisconsin herd this spring.
Ten swine from a 300-head herd in Greenwood tested positive for the pseudorabies virus. The U.S. Department of Agriculture ruled that the herd was likely to have had contact with feral swine, a reservoir for pseudorabies.
Eleven swine from a 20-head herd near Loyal also tested positive for the virus. The Loyal farm bred a boar from the Greenwood farm.
State officials tested swine from 66 operations that are within 5 miles of the Greenwood and Loyal farms or that had contact with the farms. Officials finished testing and depopulating in time to meet the USDA's 15-day deadline for retaining the state's pseudorabies-free status.
Wisconsin's infection rate peaked in 1989 with 60 commercial herds. The last case of the virus in a Wisconsin commercial herd occurred in 1998.