"That makes it clear they are the same species. Ninety-nine nucleotides on the full genome amounts to only 0.3 0.4% difference," says Fouchier. "That, of course raises new questions."
Now a third case of illness from this new virus has been identified, this time in Saudi Arabia again, but the genome sequence of that virus is not yet available.
The genome of the HCoV-EMC/2012 virus that is the focus of the mBio study was fully sequenced within a few days by combining an optimized random amplification deep sequencing approach, which covered about 90% of the genome, with conventional Sanger sequencing to confirm these draft findings.
Phylogenetic analyses place the virus within the Betacoronavirus genus, where its closest fully sequenced relatives are viruses called BtCoV-HKU4 and BtCoV-HKU5, both of which were originally isolated in Asia from Lesser bamboo bats (Tylonycteris pachypus) and Japanese house bats (Pipistrellus abramus), respectively. 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, says Fouchier. 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 impossible to tell.
Based on the similarities the HCoV-EMC/2012 virus shares with viruses from bats, and taking into account a separate serological study carried out in Saudi Arabia that showed 2,400 hospital visitors had no antibodies to the virus, Fouchier feels confident saying the virus is new to humans. That source may well be bats, he says, since Pipistrellus bats are present in Saudi Arabia and neighboring countries.
The relatedness between the HCoV-EMC/2012 virus and the virus that infected the patient in the un
|Contact: Jim Sliwa|
American Society for Microbiology