The notorious filovirus family — which includes such dangerous actors as the Ebola and Marburg viruses — seems to just keep getting bigger.
In a new study, scientists from Singapore and China have announced they found a new branch of the family, in bats in China. While there is no evidence the new virus — called Měnglà after the place where it was discovered — has caused outbreaks in people, the virus has traits similar to those that have helped its cousin viruses break into human cells.
The study was published in the journal Nature Microbiology on Monday.
The revelation follows news last summer that a new member of the Ebola family, the Bombali virus, had been found in Sierra Leone.
“Studying the genetic diversity and geographic distribution of bat-borne filoviruses is very important for risk assessment and outbreak prevention as this type of infectious disease can affect the general public without warning with devastating consequences,” senior author Wang Lin-Fa said in a statement. Wang is director of the Emerging Infectious Diseases Signature Research Program at Duke-NUS Medical in Singapore.
Genetic evidence of the virus was found in Rousettus bats in Yunnan province, in south-central China. Měnglà County is located near the intersection of China’s borders with Burma, Laos, and Vietnam. These fruit bats are sometimes called “flying foxes.”
The scientists were testing bats looking for viruses. They were not able to isolate a whole Měnglà virus, but could decode the genetic sequence.
The virus is sufficiently different from the six known Ebola viruses and the two types of Marburg virus that it belongs in its own genus, genetic analysis showed.
But work to characterize the main surface protein of the virus showed striking — and unsettling — similarities to those other viruses, which occasionally break out of nature to cause devastating outbreaks of human disease, like the one currently underway in the Democratic Republic of the Congo.
The new virus has the capacity to attach to the same cell receptors as Ebola and Marburg viruses do, the scientists reported. Work on cell lines derived from humans, monkeys, hamsters, and dogs suggests Měnglà would be able to infect them.
Overall, the scientists reported that, like Ebola and Marburg viruses, the new virus “poses a high risk of interspecies transmission.”
Dr. Jeremy Farrar, head of the Wellcome Trust, said the finding shows the importance of gaining a broader understanding of the ecology of bats, including the viruses they can harbor and the distances they can fly.
“I suspect over the next few years we’re going to see a whole group of viruses — and probably some new viruses — emerging from these studies of bat ecology. And I think it’s really important,” he said.
But whether this finding suggests southern China will experience outbreaks of Ebola-like illness remains to be seen. Farrar said more work must be done to try to ascertain if there have already been spillover events that have gone unnoticed.
“What it means for human health? I don’t think anybody knows,” Farrar told STAT. “Somebody’s just got to screen some populations around where it was found, human populations, to see how many people have got antibodies to it and how common human infection is.”