Tuesday, December 18, 2012

Scientists keep an eye on a new SARS-like virus

Coronavirus. Electron microscope photo by Phil Murphy/CDC.
In 2003, a coronavirus named SARS (for Severe Acute Respiratory Syndrome) made nine hundreds victims, most of them in Asia. Usually coronaviruses are not dangerous - they cause a cold or stomach flu -, but this one killed one among ten infected human beings. Thanks to the prompt response of the sanitary authorities all over the world, SARS was relatively rapidly controlled.

This year, a SARS-like virus has appeared in Middle East, and scientists and health officers keep a very close eye on it, as Nature News reports. At present it remains unclear whether this new virus could become a real worldwide threat, but it killed five of the nine cases known so far. 
The first cases were reported this Summer in Saudi Arabia and in Qatar, but in November evidence showed that people had been infected by the new virus in Jordan already this Spring.

No time was lost to tackle this issue, and actually many of the researchers who worked on SARS in 2003 are now working on the new coronavirus. In September the complete genome sequence of the virus (called HCoV-EMC/2012) was made available in the GenBank database. This result was published in the journal mBio last month.

The original host of the virus is the bat - also the case for SARS -, and from bats it can  move and infect other mammals, including humans. One feature of SARS has helped to reduce its dissemination in 2003: its site of infection is deep in the lungs, which makes it severe but its spreading by coughing is limited. HCoV-EMC/2012 does not bind the same human receptor than SARS (as revealed by a new study in mBio), so the infection site in the pulmonary system is still unclear. Another important difference shown by the paper is that the new virus can replicate in bat, pig, and human cells, whereas traditionally viruses are adapted to one host only. The new virus is thus potentially able to easily jump between species. Many details in the history of this new coronavirus remain unknown, however, and the forthcoming weeks should bring new and important information.

Additional news can be read in the magazine Wired, which is doing a rather extensive coverage of this story.


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