Scientists have expressed concern that a recently identified pig virus may have the potential to cause an outbreak that could threaten humans and animals. The new study, which explored the ability of the virus to infect different species, was led by researchers at the Ohio State University and Utrecht University in the Netherlands.

The paper titled “Broad receptor engagement of an emerging global coronavirus may potentiate its diverse cross-species transmissibility” was published in the journal Proceedings of the National Academy of Sciences on May 14.

“We are very worried about the emerging coronaviruses and we are worried that they will cause harm to animals and they may jump into humans,” said senior author Linda Saif, a distinguished professor of veterinary medicine at Ohio State University and an investigator at Ohio Agricultural Research and Development Center (OARDC).

Before it was initially identified in 2012 in pigs from China, porcine deltacoronavirus (PDCoV) was only found in various birds. In 2014, the virus was identified in the United States during a diarrhea outbreak in pigs from Ohio.

While no human cases have been recorded yet, the possibility looms due to the ability of the virus to infect the cells of different species. The researchers conducted tests to show how PDCoV could infect human, cat, and even chicken cells.

The lab tests also revealed how the virus infects a new host through a protein receptor called aminopeptidase N. The authors stated this could also “facilitate direct transmission of PDCoV to nonreservoir species, including humans,” which could reflect the mechanism used by the virus “to breach the species barrier between birds and mammals.”

In other words, they believe receptor interaction is the first step in virus infection of the host cell, which can play a role in determining the viral host range. Scott Kenney, an assistant professor of veterinary preventive medicine at OARDC, compared the mechanism of the receptor to a door lock.

“If the virus can pick the lock, it can get into the cell and potentially infect the host,” he said.

The concern revolves around the virus potentially being lethal if it begins spreading, similar to the outbreaks of Severe Acute Respiratory Syndrome (SARS) and Middle-East Respiratory Syndrome (MERS). However, Saif added the virus has only infected humans and other species in laboratory-cultured cells for now. 

“This doesn't prove that this virus can infect and cause disease in these other species, but that's something we obviously want to know,” she said. “We now know for sure that [PDCoV] can bind to and enter cells of humans and birds. Our next step is to look at susceptibility—can sick pigs transmit their virus to chickens, or vice versa, and to humans?”

After an outbreak began in China, SARS killed 774 people between 2002 and 2003 in 37 countries, according to the World Health Organization. Meanwhile, the on-going MERS outbreak in Saudi Arabia led to more than 1,800 cases and 787 deaths since 2012. SARS, which originated in bats before infecting humans, was also found in camels.