A virus related to SARS has claimed its sixth victim, officials announced yesterday. A British man has died of the coronavirus, called HCoV-EMC, which was first identified last year. There have been a total of 12 cases of the coronavirus in the UK, Saudi Arabia and Jordan.
Now in a new study researchers have actually quantified the infection rate of the new virus. Results show that at a cellular level EMC is as efficient at infecting human cells as the common cold. Scientists isolated cells from the lining of three healthy people’s airways and cultured them in the lab, then introduced EMC, SARS, and a common cold virus to different groups of cells.
They found that EMC did indeed replicate in the airway cells (this tissue is especially vulnerable, which explains why infected individuals suffer respiratory problems). No detectable inflammation was produced, meaning that cells’ inbuilt immune defenses didn’t even see the virus, signalling that EMC is very effective at evading immune system defenses. However, its efficiency at causing disease is yet to be determined. Many coronaviruses are similarly good at infecting human cells—ie, getting inside them and replicating—but they cause only mild disease symptoms.
Coronaviruses derive their name from the corona visible in
images such as this 1975 transmission electron micrograph
of infectious bronchitis viruses
When a 49-year-old Qatari man fell ill in England this month, doctors realized that his respiratory problems and kidney failure were due to a previously unknown virus. Earlier this year, a nearly identical virus, 99.5 percent genetically identical to be exact, killed a middle-aged Saudi man. While a new disease is always cause for caution, there have been only two confirmed cases thus far. So what’s the worry? The problem is that this new virus belongs to a family called coronaviruses, a family that includes the common cold…and the deadly and fast-spreading Severe Acute Respiratory Syndrome, or SARS.