GENEVA -- A new pneumonia-causing virus that's killed six people in the past year can infect the lining of a person's airways faster than the SARS bug, a study found, though researchers still don't know how easy it is to spread.
The so-called novel coronavirus, which is related to the pathogen that killed 774 people in 2002 and 2003, can penetrate cells that line the entry to the lungs and reach its peak ability to replicate in two days, compared with as much as four days for the SARS virus, researchers from the cantonal hospital in St. Gallen, Switzerland, wrote Tuesday in the journal mBio, which is published by the American Society for Microbiology.
Twelve cases of the virus have been confirmed, including eight in the Middle East and four in Britain, where three members of the same family were diagnosed last week, suggesting human-to-human transmission. Still, the discovery that the virus can easily get into respiratory cells doesn't mean it can easily get out again and spread through the air to other people, said Volker Thiel, who led the research.
"We don't know whether the cases we observe are the tip of the iceberg, or whether many more people are infected without showing severe symptoms," Thiel said in a statement.
One of the patients diagnosed in Britain last week died Feb. 17, the Queen Elizabeth Hospital in Birmingham said in a statement Tuesday. The patient had been receiving treatment for an unrelated long-term health condition and had a depleted immune system, the hospital said, without specifying the person's age or gender.
Testing for the new virus should be considered in patients with unexplained pneumonia, the World Health Organization said in a Feb. 16 statement. Although last week's cases suggest person-to-person infection, no sustained transmission between people has been identified, the Geneva-based agency said.
The new coronavirus is susceptible to proteins called interferons, suggesting a potential treatment, Thiel and his colleagues wrote. Interferons are commonly used to fight infection with the hepatitis C virus.
Genetic evidence suggests the virus is most closely related to a coronavirus found in bats, the WHO said in November. That makes it surprising the pathogen can so quickly infect human cells, Thiel said.
"There's a certain phase of adaptation, like we have seen for SARS," Thiel said in a telephone interview. "This is obviously not needed, at least not in the epithelium," or lining of the lungs, for the new virus.
The research was funded by the Swiss National Science Foundation, the 3R Research Foundation Switzerland, the German Ministry of Education and Research, the German Research Foundation, the Danish Cancer Society and the Danish Council for Independent Research.