Despite closing in on pseudorabies (PRV) eradication in the U.S., the infected feral pig population still threatens the commercial swine industry.

Case in point is the recent PRV case in Arkansas that was traced to casual contact with feral or wild pigs.

Even though Iowa has been in Stage IV (surveillance) since April 2003, state veterinarian John Schiltz recommends continuing PRV vaccination.

“Iowa imported approximately 15 million feeder pigs in 2003, with some of them coming from states with feral swine,” he says. “The ongoing threat of PRV remains a legitimate concern for our state's swine producers.”

In an outbreak, states require expensive quarantine and rapid depopulation of infected herds. North Carolina, for example, would require testing in a 2.5-mile radius and vaccination of all pigs to take place, says Fred Kirkland, state department of agriculture. North Carolina, in Stage V (free), exports 21,000 hogs/day.

About 520,000 breeder or feeder pigs move interstate weekly, says the U.S. Department of Agriculture.

“It is important to ensure that these trailers are thoroughly cleaned and disinfected between loads to prevent PRV spread between farms,” notes Harry Snelson, swine technical services veterinarian for Schering-Plough Animal Health. “This is particularly important during the winter when the virus may survive for prolonged periods in organic material or on cold, moist surfaces.”

Winter vaccination is a small price for PRV insurance, says Schiltz.