Scientists from Saudi Arabia and the United States have reported finding a partial match for the MERS coronavirus in a sample taken from a bat in Saudi Arabia.
The fragment of viral DNA was extracted from a fecal swab from an Egyptian tomb bat — the species' proper name is Taphozous perforatus — in the western part of the country. The bat is an insect eater, and is often found among fruit trees because the fruit attracts insects.
The small fragment is a perfect match for the corresponding portion of the MERS virus isolated from Saudi Arabia's first known case, a man who died in June 2012. The bat was found in a colony that roosted in ruins near where the man lived.
This the first time a match for the human virus — even a fragment of it — has been found in samples taken from an animal. But while the finding adds further support for the widely held suspicion that the new coronavirus originated in bats, the fragment isn't large enough to say definitely that the bat virus was identical to the MERS coronavirus, an expert said.
If the scientists had been able to sequence the full genetic blueprint of the bat virus differences between it and the human virus might have been spotted, explained Andrew Rambaut, a professor of molecular evolution at the University of Edinburgh who has been following the MERS story.
"There's still potential for it to be relatively distant if we had the complete genome," he said in an interview.
"It's definitely implicated in the story, but we don't quite know where it lies in that story."
Other transmitters suspected
The report was published online Wednesday in Emerging Infectious Diseases, a journal published by the U.S. Centers for Disease Control. It was reported by scientists from the Saudi Ministry of Health, Columbia University and the organization EcoHealth Alliance.
Lead author Dr. Ziad Memish, the Saudi deputy minister of health, said bats have always been suspected to be the original source of the virus, but there are probably other players of the chain of transmission that haven't yet been identified.
"There must be something in the middle," Memish said during a talk on MERS in Washington, D.C., that was organized and webcast by the University of Pittsburgh Medical Center's Center for Health Security.
"Is it food? Is it (an)other animal reservoir? That's something to be determined."
The finding is one that senior author, Dr. Ian Lipkin, has publicly spoken about in the past. In early July, he said that he might not publish the results because of the limited size of the fragment.
To date there have been 97 confirmed cases of MERS and 46 of those infections have ended in death.
All cases have originated from four Middle Eastern countries — Saudi Arabia, Jordan, Qatar and the United Arab Emirates. MERS infections have also been diagnosed in Britain, France, Italy, Tunisia and Germany. But in these instances the virus was brought into the country by someone who had travelled in the Middle East before getting sick or who travelled to Europe by air ambulance seeking care.