Study: Swine coronavirus could jump to people

A strain of coronavirus that has recently alarmed the swine industry could spread to humans, research from the University of North Carolina at Chapel Hill suggests.

The strain, known as swine acute diarrhea syndrome coronavirus (SADS-CoV), emerged from bats and has infected swine herds throughout China since it was first discovered in 2016, Science Daily wrote.

SADS-CoV is in the same family of viruses as the betacoronavirus SARS-CoV-2, which causes COVID-19 in humans. SADS-CoV, however, is an alphacoronavirus that causes severe diarrhea and vomiting in swine.

Lab tests showed SADS-CoV “efficiently replicated in human liver and gut cells, as well as airway cells,” demonstrating a potential danger for people. The findings were published recently in the journal PNAS.

“While many investigators focus on the emergent potential of the betacoronaviruses like SARS and MERS, actually the alphacoronaviruses may prove equally prominent — if not greater — concerns to human health, given their potential to rapidly jump between species,” said Ralph Baric, professor of epidemiology at UNC-Chapel Hill Gillings School of Global Public Health.

Baric’s lab worked with Caitlin Edwards, a research specialist and master of public health student at UNC-Chapel Hill. Edwards tested several types of cells by infecting them with a synthetic form of SADS-CoV to understand just how high the risk of cross-species contamination could be.

According to the results, a wide range of mammalian cells, including primary human lung and intestinal cells, are susceptible to infection. SADS-CoV showed a higher rate of growth in intestinal cells found in the human gut, unlike SARS-CoV-2, which primarily infects lung cells, Edwards found.

Although cross-protective herd immunity often prevents humans from contracting many coronaviruses found in animals, Edwards suggests humans have not yet developed an immunity to SADS-CoV.

“SADS-CoV is derived from bat coronaviruses called HKU2, which is a heterogenous group of viruses with a worldwide distribution,” Edwards said. “It is impossible to predict if this virus, or a closely related HKU2 bat strain, could emerge and infect human populations. However, the broad host range of SADS-CoV, coupled with an ability to replicate in primary human lung and enteric cells, demonstrates potential risk for future emergence events in human and animal populations.”