OSU calms worries about disease in pigs

May 12, 2006

CORVALLIS, Ore. – A recent outbreak of illness among swine in Oregon has 4-H members concerned about pigs they are raising for upcoming county fair competitions.

"The disease is not new in Oregon, nor does it pose any danger to humans," said Gene Pirelli, an Oregon State University Extension swine specialist. "The most important thing is to follow the biosecurity guidelines that have been in place for years to keep animals healthy at the fair."

Those general biosecurity recommendations include:

  • Vet checks should be carried out before exhibition.
  • Bio-security should be practiced with regards to cleaning and disinfection of all equipment, shoes/clothing and trailers before returning home.
  • If pigs are to be returned home, they should be quarantined for four weeks in a facility completely separate from other swine.

"Anytime we bring animals together from different farms or locations, we run the risk of passing illness from one animal to another," Pirelli said. "I always stress to participants that animals need to come to the fair with the highest possible immunity against any disease. That means raising animals with a combination of good nutrition, good housing and vaccination at the proper time."

Concern arose when several weaned pigs imported in March from Illinois became sick and died. One of the dead pigs was diagnosed with Porcine Respiratory and Reproductive Syndrome virus, a respiratory disease that is specific to pigs and can be fatal, and with the less virulent Porcine Circovirus.

None of the 87 imported pigs were showing any signs of illness before they were loaded in Illinois or upon arrival in Oregon before being distributed to 4-H and FFA members in Crook, Jefferson, Deschutes, Jackson, Linn and Benton counties, according to a report by Oregon's state veterinary office.

Following reports of respiratory illness, fever and lack of appetite among some of the imported pigs, the OSU College of Veterinary Medicine diagnosed PRRS in one of the distressed pigs from this group. They also diagnosed PCV in this animal as well as in two others from the imported group. PCV is commonly found in pigs throughout the U.S., including Oregon, and usually causes only mild infections unless it is combined with other disease-causing viruses, such as PRRS or parvovirus.

PRRS virus infects only swine and mallard ducks. Although it can be fatal to pigs, it poses no threat to humans or other animals and in no way makes eating pork a threat to human health, Pirelli said.

The PRRS virus has been circulating at low levels among pigs in Oregon since the early 1990s, according to Pirelli. It is more common in the Midwest, where there are more large-scale swine facilities. Research has shown that infected pigs are no longer a risk for passing on the infection after 60 days.

The state veterinarian, Don Hansen, stressed they do not know what specifically caused the illnesses of the other pigs in this group. "There are literally dozens of infectious agents that may cause respiratory illness in swine. However, since they traveled together from the Illinois farm, we believe there was enough time for these pigs to be exposed to any infectious agents circulating among the group during the trip."

Advising all participants in swine shows, the state veterinarian's report said that there is always potential for exposure to a wide variety of diseases at these shows, not just the viruses found in these pigs.

As a precaution, the state veterinarian's office is recommending that this group of pigs from Illinois not be mingled with other pigs until at least June 1, which is 67 days after they were delivered to Oregon.

They recommend that if these animals need to participate in weigh-in events in preparation for county fairs, that the imported pigs be weighed at a different time than other pigs in the event and that scales and associated equipment be properly disinfected after all the pigs are weighed.

They further recommend that this group of pigs be shown only at terminal shows where all participating animals are harvested following the show.

Charles Estill, a veterinarian in OSU's College of Veterinary Medicine, said the most effective control measure is to separate potentially infected pigs from other pigs.

The virus cannot tolerate heat or drying but can survive up to 11 days in water. Cleanliness, dryness and disinfection of all surfaces that may have had contact with infected pigs will remove environmental sources of infection.

For more information about PRRS, see: http://extension.oregonstate.edu/emergency/prrs.php

Author: Peg Herring
Source: Gene Pirelli, Charles Estill