Baric leads study of deadly new respiratory coronavirus

Dr. Ralph Baric

A new study led by Ralph Baric, PhD, professor of epidemiology at the UNC Gillings School of Global Public Health, examines a particularly troublesome bug, dubbed the Middle East Respiratory Syndrome coronavirus (MERS-CoV).

First detected in 2012, MERS-CoV replicates easily in human airway epithelial cells. At the time the study was published, the virus had caused at least 110 cases of illness and 52 deaths – a mortality rate of nearly 50 percent.

“MERS-CoV is the second deadly respiratory coronavirus that emerged in the 21st century, following the SARS-CoV epidemic in 2003,” Baric said.  “We are still uncertain as to the origins of these viruses and how frequently they transmit between species. In addition, vaccines and therapeutics are needed to protect the health of populations globally.”

Although the virus likely emerged from exotic animals, perhaps bats, the fact that it now can be transmitted between humans raises the cry for an in-depth study of ways the disease works and ways it can be prevented or treated.

The researchers report the synthesis of a MERS-CoV molecular clone, and the isolation of recombinant viruses that function similarly to the real virus in terms of its replication process, protein make-up and processing, and RNA expression. Significantly, working with the clone virus allowed the researchers to demonstrate that the virus preferentially replicates in a variety of different primary lung cells, which likely explains key aspects of its virulence in humans.

“The ability to manipulate the MERS-CoV genome has allowed us to isolate viruses that encode novel indicator genes which, in turn, allow us to rapidly screen for inhibitors that block virus replication and disease,” said lead author Trevor Scobey, research technician in the Gillings School’s epidemiology department.

The article, “Reverse Genetics with a Full-length Infectious cDNA of the Middle East Respiratory Syndrome Coronavirus (MERS-CoV),” was published online Sept. 16 in the Proceedings of the National Academy of Sciences (PNAS).

Co-authors, in addition to Baric and Scobey, include Boyd Yount and Jesica Swanstrom, research specialists;  Amy Sims, PhD, research assistant professor; Eric Donaldson, PhD, adjunct assistant professor; Sudhakar Agnihothram, PhD, and Rachel Graham, PhD, postdoctoral research associates; and Vineet Menachery, PhD, postdoctoral trainee, all of the Gillings School’s Department of Epidemiology; Peter Bove, research associate at the UNC Cystic Fibrosis/Pulmonary Research and Treatment Center; Scott Randell, PhD, associate professor, and Jeeho Kim, research technician, both of the UNC Department of Cell Biology and Physiology and the Cystic Fibrosis/Pulmonary Research and Treatment Center; and Sonia Grego, of the Center for Materials and Electronic Technologies at RTI International, in Durham, N.C.