New Pig Virus could Pose Threat to Humans

A new virus found in pigs may pose a threat to people, new research suggests.

Researchers found the virus was able to infect cultured human cells and cells of other species in a lab. The discovery is raising concerns about a potentially dangerous outbreak in the United States.

The pig virus, known as Porcine deltacoronavirus, was first identified in China in 2012. It was found in pigs but it was not associated with disease.

Two years later, it was discovered in the United States during an outbreak of diarrhea among pigs in Ohio. Since then, it's been detected in other countries. Young pigs infected with the virus develop severe diarrhea and vomiting that can be deadly.

To date, no human cases of the disease have been reported. But scientists are worried that the virus could infect people due to its similarity to the viruses responsible for the outbreaks of SARS (severe acute respiratory syndrome) and MERS (Middle East respiratory syndrome).

"Before it was found in pigs -- including in the Ohio outbreak -- it had only been found in various birds," said the study's senior author, Linda Saif, a professor of veterinary preventive medicine who's with Ohio State University's Food Animal Health Research Program. "We're very concerned about emerging coronaviruses and worry about the harm they can do to animals and their potential to jump to humans."

The ability of a virus to jump between species depends on its ability to find receptors on the cells of people or animals, explained the study's lead researcher, Scott Kenney.

"A receptor is like a lock in the door. If the virus can pick the lock, it can get into the cell and potentially infect the host," Kenney said in a university news release. He's an assistant professor of veterinary preventive medicine at the Ohio Agricultural Research and Development Center.

To investigate the pig virus' potential to jump to other species, researchers at Ohio State and Utrecht University in the Netherlands honed in on a particular cellular receptor called aminopeptidase N.

The study, published online this week in the journal PNAS, showed the virus could bind to the receptor in human cells and to cells from cats and chickens.

However, these were cells cultured in a lab setting.

The researchers added that their findings don't prove that the pig virus can cause disease in other species. "But that's something we obviously want to know," Saif said.

The team plans to continue its investigation, looking for antibodies in human blood that would indicate that the pig virus may have infected people.

"We now know for sure that [the pig virus] can bind to and enter cells of humans and birds," Saif said. "Our next step is to look at susceptibility -- can sick pigs transmit their virus to chickens, or vice versa, and to humans?"

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