Swine coronavirus has potential to infect humans: Study

The coronavirus strain known as Swine Acute Diarrhoea Syndrome Coronavirus (SADS-CoV), emerged from bats and has infected swine herds throughout China since it was first discovered in 2016.

The outbreak of such an illness has the potential to wreak economic havoc on many countries across the globe that rely on the pork industry.

The virus' potential threat to people was demonstrated in lab tests that revealed SADS-CoV efficiently replicated in human liver and gut cells as well as airway cells, reported the study published in the journal 'Proceedings of the National Academy of Sciences'.

"Though it is from the same family of viruses as the betacoronavirus SARS-CoV-2 which causes the respiratory illness Covid-19 in humans, SADS-CoV is an alphacoronavirus that causes gastrointestinal illness in swine," said the study authors from the University of North Carolina in the US.

The virus causes severe diarrhoea and vomiting and has been especially deadly to young piglets.

SADS-COV is also distinct from two circulating common cold alphacoronaviruses in humans, HCoV-229E and HCoV-NL63.

"While many investigators focus on the emergent potential of the betacoronaviruses like SARS and MERS, the alphacoronaviruses may prove equally prominent -- if not greater -- concerns to human health given their potential to rapidly jump between species," said researcher Ralph Baric from the UNC.

Baric worked with Caitlin Edwards, a research specialist at the UNC, on the study which suggests humans may be susceptible to spillover of SADS-CoV.

Edwards, the study's first author, 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.

Evidence from the study indicates that a wide range of mammalian cells, including primary human lung and intestinal cells, are susceptible to infection.

According to Edwards, SADS-CoV shows a higher rate of growth in intestinal cells found in the human gut unlike SARS-CoV-2 which primarily infects lung cells.

Cross-protective herd immunity often prevents humans from contracting many coronaviruses found in animals. However, results from the testing done by Edwards and her team suggest that humans have not yet developed such 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 population.

"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 of infections in human and animal populations," Edwards noted.