Zoonotic Coronavirus Genetically Analyzed

The results of the sequencing and analysis of this virus could be used to develop diagnostic methods and possibly in creating therapies and vaccines if they are eventually needed for this emerging disease.

Molecular virologists at the Erasmus Medical Center (Rotterdam, The Netherlands) carried out a genomic characterization of a newly discovered coronavirus, known as HCoV-EMC/2012 virus, which is associated with acute respiratory distress syndrome in humans.

The scientists used a combination of approaches, including deep sequencing, cycle sequencing on a more traditional capillary sequencer, and determination of the genomic termini by rapid amplification of complementary cDNA ends (RACE), the complete genome sequence of HCoV-EMC/2012 was determined from material that had been subjected to passage in cell culture six times.

Phylogenetic analyses place the virus within the Betacoronavirus genus, where its closest fully sequenced relatives are viruses called BtCoV-HKU4 from Tylonycteris pachypus (Lesser bamboo bats) and BtCoV-HKU5 from Pipistrellus abramus (Japanese house bat) both of which were originally isolated in Asia. The HCoV-EMC/2012 bears only 77% sequence similarity with the BtCoV-HKU5 virus, however, making it distinct enough to be called a novel species of virus. A partial sequence from a virus that was isolated from a species of bat in the Netherlands appears to be a closer match with HCoV-EMC/2012, but without a full genome sequence, the exact degree of relatedness is unknown.

Ron Fouchier, PhD, who led the study, said: "The virus is most closely related to viruses in bats found in Asia, and there are no human viruses closely related to it. Therefore, we speculate that it comes from an animal source. A well-annotated genome sequence is crucial to further the development of diagnostic methods, and antivirals and vaccines that might be needed. Considering that three cases of disease from the virus have already been identified we certainly need the diagnostics already.” The study was published on November 20, 2012, in the journal mBio.

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