Swine on two farms in Clark County in central Wisconsin contracted the pseudorabies virus, which can cause respiratory and reproductive problems in hogs. After identifying registered farms within a five-mile radius of the infected farms, officials spent four more days tracking down places where unregistered livestock was kept.

Half the 62 sites in the area were not registered, said Rod Nilsestuen, Wisconsin's agriculture chief.

"This time it was pseudorabies - serious and fatal in many cases, but not a disease that moves terribly fast or that harms humans," he said. "What if it had been foot-and-mouth disease? What if it had been the deadly strain of avian influenza? We were lucky - this time."

A year and a half ago, Wisconsin became the first state to pass legislation requiring livestock premise registration to help prevent the spread of disease by enabling officials to track down animals within 48 hours. The legislation covers numerous types of livestock, including cattle, bison, llamas, goats and ostriches.

The National Animal Identification System said Wisconsin had 57,494 of the 391,884 livestock premises registered nationally as of May 14. That's more than twice as many as the next three states - Indiana, Pennsylvania and Texas - all of which had 27,000 to 28,000.

Source: FortWayne.com