Emerging SARS-Like Virus Well-Suited to Attack Humans: Study
TUESDAY Feb. 19, 2013 -- The new SARS-like "coronavirus" that first emerged in the Middle East can invade the lungs and immune system as easily as the common cold, according to a new study.
But in the event of a large-scale outbreak, researchers in Switzerland found the virus -- known as HCoV-EMC -- may be treatable with components of the immune system, known as interferons. This immunotherapy has shown promise in the treatment of the respiratory disease SARS and hepatitis C, the study authors said.
"Surprisingly, this coronavirus grows very efficiently on human epithelial cells," said study co-author Volker Thiel of the Institute of Immunobiology at Kantonal Hospital in St. Gallen, in a news release from the American Society for Microbiology. Epithelial cells line hollow organs and glands.
"The other thing we found is that the viruses [HCoV-EMC, SARS, and the common cold virus] are all similar in terms of host responses: they don't provoke a huge innate immune response," he said.
The study was published online Feb. 19 in mBio.
HCoV-EMC, which may have jumped from animal to human very recently, was first isolated in June after a man in Saudi Arabia died from a severe respiratory infection and kidney failure. Following his death, health officials identified 11 more people infected with the virus, the latest in Great Britain. So far, six of the 12 people with known infections have died. Nearly all patients have lived or traveled in the Middle East.
Concerns have been raised that the new strain could trigger a pandemic similar to the SARS outbreak of 2002-03, which infected more than 8,000 people and killed 774.
"We don't know whether the cases we observed are the tip of the iceberg, or whether many more people are infected without showing severe symptoms," noted Thiel.
The World Health Organization on Saturday said that doctors should test patients for the new coronavirus if they have unexplained pneumonia or unexplained complicated respiratory illness not responding to treatment.
So far, no cases of the coronavirus have been reported in the United States, according to the U.S. Centers for Disease Control and Prevention.
To test the new virus, the researchers used cultured bronchial cells to mimic the lining of the human airway. Although this lining is a key barrier against respiratory viruses, the study revealed these cells didn't mount a big defense against HCoV-EMC. Instead, they found human lungs are highly susceptible to the virus, which can multiply at a faster initial rate than SARS.
The study authors noted, however, that pre-treating the airway with proteins that play a critical role in immune response to infections -- known as lambda-type interferons -- significantly reduced the number of infected cells.
Although their findings suggest there is promise for an effective treatment against HCoV-EMC, the researchers added ongoing cooperation between scientists and health agencies around the world is needed to prevent outbreaks of this virus and other diseases.
The World Health Organization provides more information on coronavirus infections.
Posted: February 2013