The middle East respiratory syndrome–how worried should we be? MBio 2013

syndrome coronavirus (MERS-CoV), has been identified as the cause of a highly lethal pneumonia in patients in theMiddle East and in travelers from this region. Over the past 9 months, since the virus was first isolated, much has been learned about the biol-ogy of the virus. It is now clear that MERS-CoV is transmissible from person to person, and its close relationship with several bat coronaviruses suggests that these animals may be the ultimate source of the infection. However, many key issues need to be ad-dressed, including identification of the proximate, presumably zoonotic, source of the infection, the prevalence of the infection in human populations, details regarding clinical and pathological features of the human infection, the establishment of a small rodent model for the infection, and the virological and immune basis for the severe disease observed in most patients. Most im-portantly, we do not know whether a MERS-CoV epidemic is likely or not. Infection with the virus has so far resulted in only 91 cases and 46 deaths (as of 29 July 2013), but it is nonetheless setting off alarm bells among public health officials, includingMar-garet Chan, Director-General of theWorld Health Organization, who calledMERS-CoV “a threat to the entire world. ” This arti-cle reviews some of the progress that has beenmade and discusses some of the questions that need to be answered. A NOVEL VIRUS IS IDENTIFIED IN SAUDI ARABIA Middle East respiratory syndrome-coronavirus (MERS-CoV)was initially isolated in September 2012 from a patient in Saudi Arabia who had developed a lethal infection characterized by pneumonia and renal failure (1). A nearly identical virus wa