The Iowa State College of Veterinary Medicine has received more than $1.2 million in research grants to study a virus having a large economic impact on swine producers across the nation.

Porcine reproductive and respiratory syndrome (PRRS) is one of the major swine diseases in the country increasing six-fold in the number of cases in the last two years, said Patrick Halbur, a pathologist at ISU’s Veterinary Diagnostic Laboratory.

An estimated 60 percent of the swine herds in the United States are infected with the disease, said Perm Paul, associate dean for research at ISU’s College of Veterinary Medicine.

PRRS causes reproductive problems with swine and an increase in abortions after pregnancy. It may also cause pneumonia in the pigs, making it difficult for them to breathe. The virus persists for a long time in the hogs, though they may appear healthy. PRRS can be compared to Acquired Immune Deficiency Syndrome (AIDS) in people, Paul said.

The disease was first identified in the late 1980s and ISU researchers began to study the virus in 1991. This summer larger outbreaks occurred that caused between 10 to 50 percent of pregnant females to abort their litters within a period of one to five weeks, Halbur said. There was also a higher mortality rate of females who have had abortions.

People from the ISU Veterinary Diagnostic Lab visited the infected herds. They isolated the virus from the herds and are making experimental models to study it.

Researchers are working to develop diagnostic tests for detection of the virus. They have looked at how the disease is spread among the pigs. It appears boars shed the virus through their semen, Paul said.

Halbur said researchers are comparing the effects of the virus between herds. He said some herds can be devastated while others still have very good years.

Researchers are also interested in what other pathogens may be associated with PRRS in these herds. Paul said researchers are concerned that the virus could be mutating, which makes it more difficult to stop.

To prevent the swine from contracting PRRS, farmers should work with veterinarians to make sure the animals coming into their herds do not have the virus. There are two vaccines available to farmers for the virus. After a break-out, there are methods a farmer can use to eliminate the disease from the farm, Paul said.

If farmers suspect their herds have contracted the virus they should contact their veterinarian. Questions about controlling the disease can also be directed to ISU’s Veterinary Diagnostics Lab.

“The College of Veterinary Medicine is committed to helping to serve the livestock industry,” Paul said. “We are very aggressive to work with the industry to make a contribution.”

Funding for the research project has come from the United States Department of Agriculture, private companies, the Healthy Livestock Initiative Council, the Iowa Livestock Health Advisory Council, the National Pork Producers Council and the Iowa Pork Producers Association.