Tests on Clark County swine in the second pseudorabies quarantine area were negative, Wisconsin State Veterinarian Robert Ehlenfeldt announced and those herds will be released from quarantine immediately.
Negative test results from the first quarantine area were reported April 25. Two infected herds were destroyed April 27. Completion of testing and herd depopulation in the two areas mean that state animal health officials met the U.S. Department of Agriculture's 15-day deadline for finishing those tasks and retaining Wisconsin's pseudorabies-free status.
Blood samples were drawn Monday and Tuesday, April 30-May 1, from swine on farms within five miles of the infected herd near Loyal. Animals from two herds outside the area, but which had purchased swine from the infected herd, were also tested. The last test results came back this afternoon from Wisconsin Veterinary Diagnostic Laboratory. All were negative.
Under federal rules, those farms within two miles of the two infected herds will need to be retested after the infected farms are cleaned and disinfected, but will not be quarantined in the meantime.
In all, 35 herds were tested in this round: 33 within the five-mile area around the infected farm and two that had bought hogs from the infected herd. Thirty-two herds were tested in connection with the first infected herd, located near Greenwood. Five of those were "contact herds" that had some exposure to animals in the infected herd, and 27 were within five miles of the infected farm.
All told, swine from 68 farms were tested, including the two infected herds. A total of 21 animals tested positive: 10 from the original 300-head herd near Greenwood and 11 from a herd near Loyal. Animals in the two herds had been exposed to one another when a boar from the Greenwood farm was taken to the Loyal farm for use in breeding.
Owners of the two infected premises must clean feed and manure residue from all equipment, floors, walls, etc. When they are finished, staff from the Department of Agriculture, Trade and Consumer Protection or the U.S. Department of Agriculture will disinfect the property. From 30 to 60 days later, swine herds on farms within two miles will be retested for pseudorabies. If all tests are negative, owners of the infected premises can bring swine onto their farms again.
The first pseudorabies-infected herd came to light as a result of routine surveillance at slaughter. The USDA notified Wisconsin April 24 that, because it was likely that both herds had been exposed to feral swine, the state would not lose its pseudorabies-free status as long as it met the 15-day deadline. The USDA considers infected feral swine less of a disease risk to the nation's hog industry than infection in commercial herds.
Losing Wisconsin's pseudorabies-free status would mean that producers had to test for the disease before shipping animals out of state. In 2005, Wisconsin producers shipped 182,000 swine out of state. Wisconsin's pork production in 2005 was worth $120 million, with a total swine herd of 430,000 animals.
The state of Michigan banned swine imports from Wisconsin when the pseudorabies outbreak occurred, and Kansas imposed some testing requirements on Wisconsin swine entering that state. Those restrictions remain in place until further notice. No other states took any action.