Thursday, May 16, 2013

PRO/AH/EDR> Novel coronavirus - Eastern Mediterranean (29): MERS-CoV, ICTV nomenclature

Published Date: 2013-05-16 16:30:42
Archive Number: 20130516.1717833

Date: Wed 15 May 2013
Source: Journal of Virology [summ., edited]

[Ref: de Groot RJ and members of the ICTV Study Group of the ICTV: Middle East Respiratory Syndrome Coronavirus (MERS-CoV): Announcement of the Coronavirus Study Group. J. Virol. doi:10.1128/JVI.01244-13]
During the summer of 2012, in Jeddah, Saudi Arabia a hitherto unknown coronavirus was isolated from the sputum of a patient with acute pneumonia and renal failure. The infection appears to be geographically linked -- at least for now -- to the Middle East, in particular the Arabian Peninsula.

Since the initial discovery, isolates of the virus have been described in the scientific literature, databases, and popular press under various names (such as, human betacoronavirus 2c EMC, human betacoronavirus 2c England-Qatar, human betacoronavirus 2C Jordan-N3, betacoronavirus England 1) with novel coronavirus (NCoV) as the one used most often. As this lack of uniformity in virus nomenclature complicates communication both in the research field and with health-care authorities, governments and the general public, the Coronavirus Study Group (CSG) of the International Committee on Taxonomy of Viruses (ICTV) took the lead to address this issue. After careful consideration and broad consultation, the CSG has decided to call the new coronavirus "Middle East Respiratory Syndrome Coronavirus" (MERS-CoV).

This name is endorsed by the discoverers of the virus and other researchers that pioneered MERS-CoV studies, by the World Health Organization and by the Saudi Ministry of Health. We strongly recommend the use of this name in scientific and other communications. New MERS-CoV isolates or variants detected by RT-PCR may be provided with an affix, analogous to convention in influenza virus nomenclature (host/country of origin + strain identification number/year; such as, MERS-CoV Hu/Jordan-N3/2012).

Within the subfamily _Coronavirinae_ (family _Coronaviridae_), this novel virus is a representative of a new yet-to-be established species in lineage C of the genus _Betacoronavirus_, which currently only includes the species _Tylonycteris bat coronavirus HKU4_ and _Pipistrellus bat coronavirus HKU5_. The novel coronavirus seems most closely related to as yet unclassified viruses from insectivorous European and African bats in the _Vespertilionidae_ and _Nycteridae_ families, respectively. The epidemiological data available suggest that the infection is primarily zoonotic in nature. [Interested readers should access the original document to view the phylogenetic relationships among members of the subfamily _Coronavirinae_ and the relative taxonomic status of MERS-CoV. - Mod.CP]. A rooted Neighbor-Joining tree was generated from amino acid sequence. The tree shows the four main monophyletic clusters, corresponding to genera _Alpha-, Beta- Gamma- and Deltacoronavirus_, and the position of MERS-CoV.

The scarce epidemiological data available suggest that the infection is primarily zoonotic in nature with limited human-to-human transmission. From what is already know of coronavirus biology and from the accumulating evidence for this particular virus, bats appear to be the natural host, and it would be tempting to assume that these animals are also the immediate source. However, this is difficult to reconcile with the fact that most patients were unlikely to have been exposed directly to bats, or with the close genetic relationship between the human isolates, indicative of a recent bottleneck. A more likely scenario is that a single variant from a spectrum of related betacoronaviruses in bats successfully crossed over to and rapidly established itself in (an) intermediate animal host species (at least in the Middle East), with subsequent incidental spill-over into the human population. Such spill over events would be facilitated through frequent intermediate host-human interactions and perhaps through viral adaptations acquired during the initial species jump. Although at present, there is no evidence for sustained community transmission, the obvious concern is that the virus may take the next step and adapt to efficient human-to-human transmission.

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[Interested readers should access the original document to read the full text and view the illustration showing Phylogenetic relationships among members of the subfamily _Coronavirinae_ and the taxonomic position of MERS-CoV, available via

As the epidemiology and host preference of this virus are still incomplete, it seems prudent to refrain from labeling MERS-CoV as a "human coronavirus", at least for the time being. Accordingly, henceforth ProMED-mail will adopt the new nomenclature recommended by the Coronavirus Study Group of the ICTV. - Mod.CP]

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