If rhesus macaques are good stand-ins for humans in studying Middle East respiratory syndrome coronavirus (MERS-CoV), the virus prefers the environment deep in the lungs, a finding that may help explain some features of the disease in humans, according to new research.
The scientists say that in macaques, the virus mainly affects the lower respiratory tract, which may help explain why the human disease is often severe but does not spread very easily from person to person.
The report by researchers from the US National Institute of Allergy and Infectious Diseases, with colleagues from other US centers, France, and Canada, was released online today by the Proceedings of the National Academy of Sciences. The same group reported recently that a combination of interferon and ribavirin improved MERS-CoV outcomes in macaques.
The team, led by Vincent J. Munster, PhD, of the NIAID lab in Hamilton, Mont., inoculated six macaques with high doses of MERS-CoV that was derived from the original 2012 isolate. They found that mild to moderate pneumonia developed quickly but didn't last very long.
"Clinical signs, virus shedding, virus replication in respiratory tissues, gene expression, and cytokine and chemokine profiles peaked early in infection and decreased over time," the report says. Virus amounts in nasal and lung samples were highest on the first day after infection and then dropped, although two of three macaques were still shedding virus after 6 days.