Is the new coronavirus the next SARS? A Commentary in mBio comes on the same week scientists are convening at a WHO meeting in Cairo to share information about the novel coronavirus that is causing alarm in the public health community. In their Commentary, Stanley Perlman and Jincun Zhao of the University of Iowa discuss the recent work of Muller et al., delving into important details about the virus’ receptor on human cells and its troubling ability to infect numerous different species.
In December, Muller et al. revealed that the new coronavirus, called HCoV-EMC, does not share the same receptor as SARS. So, what receptor does HCoV-EMC use? The pattern of infection could offer hints, say Perlman and Zhao. Avian H5N1 flu also causes severe infection but limited transmissibility, so the H5N1 receptor, glycans that contain a terminal α2,3-linked sialic acid, may have something in common with the HCoV-EMC receptor. However, if, like SARS, the receptor for HCoV-EMC is a protein, it is probably distributed in the human lung in much the same way as the SARS receptor: localized to the deeper parts of the lung, a location that necessarily limits spread from person to person.
Sialic acid or protein, finding the receptor is imperative, write Perlman and Zhao, not only for disease control, but also for understanding how the virus apparently ropes the renal system into the infection, a unique feature among coronaviruses.
The broad host range of the virus is yet another unique feature, say Perlman and Zhao. How is it that bats can (apparently) carry HCoV-EMC without getting sick? Understanding the bat response to the virus could help us understand the human response and point the direction to drugs and other therapies to diminish the impact of the disease.
Will HCoV-EMC become a global problem? Perlman and Zhao say the future is uncertain. As a first step, diagnosing past and present HCoV-EMC infections is critical for figuring out how common and deadly the virus is. If the virus infects humans only rarely it may not become the major health issue health agencies worry about.