Is Ebola virus one-up against bats?

New York: Ebola virus and bats have been waging a molecular battle for survival that may have started at least 25 million years ago, revealed a new study led by an Indian-origin scientist.

The findings shed light on the biological factors that determine which bat species may harbour the virus between outbreaks in humans and how bats may transmit the virus to people.

"We knew from our previous research that Ebola virus infects host cells by attaching its surface glycoprotein to a host cell receptor called NPC1," said study co-leader Kartik Chandran from Albert Einstein College of Medicine.

"Here, we show how bats have evolved to resist Ebola infection and how, in turn, the virus could have evolved to overcome that resistance," Chandran explained.

Outbreaks of Ebola virus disease among humans are thought to begin when a person comes into contact with a wild animal carrying Ebola virus.

"Identifying potential animal reservoir hosts for Ebola virus will provide a crucial guide for public health prevention and response programmes going forward," said study co-leader John Dye from the US Army Medical Research Institute of Infectious Diseases.

"Unlike HIV or influenza virus, Ebola virus stays hidden in an unknown natural reservoir between outbreaks," Dye added.

Chandran and colleagues exposed cells from four types of African bats to several filoviruses, including Ebola virus.

Cells from only one type of bat proved resistant to Ebola virus infection - the African straw-coloured fruit bat - which is commonly hunted for bushmeat in West Africa and migrates long distances.

So the African straw-coloured fruit bat -- suspected as an Ebola virus reservoir in the recent Western African epidemic -- was probably not guilty.

Interestingly, some non-Ebola filoviruses were able to infect cells from all of the types of bats tested, including the African straw-coloured fruit bat.

The authors proposed that genetic changes in the glycoprotein sequences of some filoviruses may have evolved to counteract changes in the NPC1 sequences of their bat hosts.

The study was published online in the journal eLife.