In June, a 60-year-old man checked into a hospital in Jedda, Saudi Arabia, with a mysterious illness. The man, who had acute pneumonia and failing kidneys, eventually died.
Now, the genetic sequencing of the virus behind his death suggests it was a new one, and it came from Asian bats. The findings, which were published Nov. 20 in the journal mBio, may help scientists understand what makes the mysterious virus so deadly.
"The virus is most closely related to viruses in bats found in Asia, and there are no human viruses closely related to it," said study co-author Ron Fouchier, of the Erasmus Medical Center in the Netherlands, in a statement. "Therefore, we speculate that it comes from an animal source."
In general, human illness from animal diseases has been on the rise, but bats are an especially deadly reservoir for viruses. In addition to harboring rabies, bats may have been the initial hosts of hemorrhagic fevers such as the Ebola virus and deadly brain fevers such as the Nipah virus, scientists say.
Since the first case was reported, two other people have fallen ill, including a man from London who was visiting neighboring Qatar and another man in Saudi Arabia.
In the new study, the team sequenced the genome of the virus, finding it resembles those of two other viruses normally found in the flying mammals. The related viruses live in two other bat species: Lesser bamboo bats (Tylonycteris pachypus) and Japanese house bats (Pipistrellus abramus), which live throughout Saudi Arabia and the Middle East.
Because the scientists tested thousands of Saudi hospital visitors and found no traces of antibodies to the disease, the team believes the virus has newly emerged in humans.
The new genetic sequence also reveals the pathogen belongs to a family of viruses that includes both the common cold and severe acute respiratory syndrome (SARS). SARS first emerged in Asia in 2002 and has killed nearly 800 people as of 2003, according to the Centers for Disease Control and Prevention
The genetic sequence of the virus in two of the patients differs enough that it's possible the two could have emerged from separate bat colonies.
"We really need to understand whether these viruses are coming from a single source or multiple sources," Fouchier said in a statement.