A group of ISU professors are working on a swine vaccine made with genetically modified corn in hopes of preventing an emerging virus.

The virus, porcine reproductive and respiratory syndrome, surfaced in 1989 and since then has accounted for an annual $600 million loss to the U.S. swine industry, said Hank Harris, professor of animal science.

There are vaccinations available by needle injections, but improved vaccines are needed that can be administered more easily, Harris said.

From a reproductive standpoint, the virus can cause infertility or abortion in sows, or the piglets can be born dead or weak, he said, and if the piglets are born alive, over time, the respiratory form of he syndrome will often affect them as they mature.

Although it is difficult to find vaccines that protect against the costly virus, Harris and other professors are optimistic about genetically modifying corn in order to vaccinate pigs against the virus.

A portion of the virus has already been identified, and researchers believe it is going to be capable of providing immunity to animals, said Chad Stahl, associate professor of animal science.

“Basically, we want to find a way to identify a vaccine that would work against the virus and produce it in corn so we can feed it to the animals,” Stahl said.

Kan Wang, director of the Center for Plant and Transformation, has already produced a potent drug-augmenting agent that causes an immune response when it is fed to animals, he said.

“There’s a link in the immune system from the intestinal tract to the respiratory tract,” Harris said. “So, if you stimulate the intestinal tract with a vaccine antigen, then immune cells will be stimulated along the intestinal tract which will then migrate to the lung and express antibody in the lung.”

In other words, when the pig is fed an appropriate amount of protein, it will hopefully get vaccinated, Wang said.

“We hope that this will be a much more effective vaccine than what is currently available,” Harris said.

Not only will vaccinating pigs through genetically modified corn hopefully be more effective, it will also offer many advantages to producers, Stahl said.

The ultimate advantage is the reduction of cost, he said.

“By having a product that is produced in corn and can be fed to the animals, it’s going to be cheaper than the production of a pharmaceutical,” Stahl said.

The ability to produce a high value product, like a vaccine in corn, could also offer a tremendous economic boom the state of Iowa, he said.

Another big advantage of oral vaccinations is that corn could be included in their regular diet, Stahl said.

If the vaccination does not have to be injected, it should be more economical to administer, Harris said.

Not only will the vaccination be easier for producers, pigs will not have to be handled as often, which will reduce their stress levels, Stahl said.

Young pigs can become stressed by over handling, like getting injected with a vaccination, he said. This stress can cause them to not eat for a day, which is very crucial because pigs have such a short birth-to-market cycle, Stahl said.

Eliminating stressful injections to the pigs will cause them to perform better, he said.