A new study reveals that the new SARS-like virus which has been causing infections in the Middle East behaves unusually in laboratory testing.
The unexpected behaviour of the virus may help to explain the pattern of spread of the cases so far, says senior author Christian Drosten, a leading coronavirus expert.
In essence, the new coronavirus is promiscuous, a term the virologists who authored the study use to describe the fact that it will grow in a variety of different types of animal cells, including cells from people, pigs and several species of bats.
That is not true for other known coronaviruses, which typically only grow in cells from the species they infect, says Drosten, who is the director of the institute of virology at the University of Bonn Medical Center, in Bonn, Germany.
Dutch virologist Ron Fouchier agrees that the finding is surprising.
"This is certainly unusual for a (corona)virus to have such a broad cellular host range," says Fouchier, a senior scientist with Erasmus Medical Centre in Rotterdam. Fouchier is also an author of the paper.
"There is something usual about this virus."
The virus goes by the name hCoV-EMC, which is short for human coronavirus Erasmus Medical Centre. Fouchier's lab was the first to sequence the full genetic code of the new virus.
It is known to have infected at least nine people from April onward, with cases recorded in Jordan, Saudi Arabia and Qatar. Five of the infected people have died.
For this study, the researchers wanted to see if the new virus uses the same cell receptor as the virus that caused SARS. It was also a coronavirus.
Finding out what cells the new virus latches onto would help scientists assess the risk it poses.
For instance, the SARS virus attached to receptors found deep in human lungs. That meant in order to get sick, people had to have been exposed to a large dose of the virus, and have breathed it deep into their lungs.
That probably explains why SARS made many of its victims so very ill; SARS killed roughly 11 per cent of the people it infected.
But it also likely limited the SARS virus's ability to spread easily from person to person and may have helped in the eventual containment of the 2003 outbreak.
The EMC virus does not use the same receptor that SARS does, the scientists found. At the time of the writing of the paper, published in the journal mBio, they hadn't managed to find the receptor the EMC virus uses.
But they did discover that it will grow in cells from five different species of bats, and in cells from pigs and humans. That is "absolutely unique among coronaviruses," they wrote.