November 20, 2012
Human Coronavirus Linked To One Found In Bats
Lee Rannals for redOrbit.com — Your Universe Online
According to a genetic analysis published in mBio, the virus that killed a man in Jeddah, Saudi Arabia earlier this year is linked to viruses found in bats.
Researchers studied the genome of the HCoV-EMC/2012 virus to understand its relatedness to other viruses and possible sources. The results of the sequencing and analysis could be used to help develop therapies and vaccines if they are needed for this emerging disease.
"The virus is most closely related to viruses in bats found in Asia, and there are no human viruses closely related to it," Ron Fouchier of the Erasmus Medical Center in the Netherlands, who headed up the study, said in a statement. "Therefore, we speculate that it comes from an animal source."
The 60-year-old man in Saudi Arabia suffered from acute pneumonia and renal failure before his death, and this was linked to coronavirus. This virus emerged in 2002 and eventually lead to the deaths of over 900 people.
HCoV-EMC/2012 is under increased scrutiny, as two other patients suffering from infections with similar viruses have been identified. Since the Saudi Arabian patient died in June, an individual from Qatar has been diagnosed with a similar condition and is being cared for at a hospital in London.
Researchers published the full genomic sequence of the virus from that patient and made it available in the mBio paper.
"That makes it clear they are the same species. Ninety-nine nucleotides on the full genome amounts to only 0.3 — 0.4% difference," Fouchier said in the statement. "That, of course raises new questions."
A third case of illness from this new virus has been identified, but the genome sequence of that virus is not yet available.
HCoV-EMC/2012 is just a 77 percent sequence similarity with the Betacoronavirus genus, which are the closest fully sequence relatives. This makes the virus distinct enough to call it a novel species.
Based on the similarities that the virus has with viruses from bats, Fouchier feels that the virus is new to humans, and that the source may as well be bats.
Fouchier said that the HCoV-EMC/2012 virus and the one with the infected patient in the London hospital is interesting because they are similar enough to be the same species, but different enough that they are probably not directly linked.
"It is unlikely they would be infected from the same source. We really need to understand whether these viruses are coming from a single source or multiple sources" before more cases come to light, he said in the statement.
The genome sequence of the HCoV-EMC/2012 virus will also enable scientists to study the virus in more detail. Fouchier said that making synthetic copies of the virus genome will enable scientists to reconstruct the virus in the lab and study its properties to identify the sources of its virulence.
"A well-annotated genome sequence is crucial to further the development of diagnostic methods and antivirals and vaccines that might be needed," Fouchier said in the statement. When taking into account that three cases of disease from the virus have already been identified, he says, "we certainly need the diagnostics already."
"Whether we would need antivirals and vaccines? Well, I certainly hope not," says Fouchier.