Bat cave study sheds new light on origin of SARS virus

November 30, 2017

Genetic recombination between viral strains in bats may have produced the direct evolutionary ancestor of the strain that caused a deadly outbreak of severe acute respiratory syndrome (SARS) in humans, according to new research published in PLOS Pathogens.

In late 2002, a SARS pandemic broke out in southern China, ultimately killing hundreds of people in dozens of countries by the summer of 2003. Scientists traced the outbreak back to horseshoe bats, hypothesizing that the culprit, SARS coronavirus, originated in these animals and then spread either directly to humans or to animals later purchased by humans at markets.

However, the details of the outbreak's origin remain unclear. SARS strains found in bats are genetically distinct from the specific SARS strain that caused the outbreak, suggesting that known bat strains did not directly evolve into the outbreak strain.

To address this issue, Ben Hu of the Chinese Academy of Sciences in Wuhan, China, and colleagues spent five years studying SARS viruses found in multiple species of horseshoe bats living in a single cave in Yunnan Province, China. In the new study, the researchers identified 11 new strains of SARS virus and sequenced their full genomes to uncover their evolutionary relationships.

Genome analysis revealed that the newly identified bat strains, as well as several strains identified in a previous study of the same bat cave, contained all the essential genetic building blocks of the human SARS coronavirus. In some of the strains, for instance, portions of a gene known as the S gene showed high genetic similarity to the same regions found in the SARS coronavirus genome.

Based on their genetic analysis, the researchers hypothesize that genetic recombination between precursor strains that later evolved into the newly identified strains may also have given rise to a strain that directly evolved into SARS coronavirus.

Additional lab experiments showed that some of the newly identified bat strains are capable of entering human cells via the same cellular receptor employed by SARS coronavirus. This suggests that the bat cave contains strains that could potentially be directly transmitted to humans.

Overall, these findings provide new insights into the evolutionary origin of SARS coronavirus. Because of the potential risk of existing bat strains spreading to humans, the researchers propose continued monitoring of the cave they studied, as well as other sites that may pose similar risk.

"Rhinolophus bats in China harbor genetically diverse SARS-related coronaviruses," the authors explain, "which may have given rise to the direct progenitor of SARS coronavirus after recombination."
-end-
In your coverage please use this URL to provide access to the freely available article in PLOS Pathogens: http://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1006698

Citation: Hu B, Zeng L-P, Yang X-L, Ge X-Y, Zhang W, Li B, et al. (2017) Discovery of a rich gene pool of bat SARS-related coronaviruses provides new insights into the origin of SARS coronavirus. PLoS Pathog 13(11): e1006698. https://doi.org/10.1371/journal.ppat.1006698

Funding: This work was jointly funded by National Natural Science Foundation of China (81290341, 31621061) to ZLS, China Mega-Project for Infectious Disease (2014ZX10004001-003) to ZLS, Scientific and technological basis special project (2013FY113500) to YZZ and ZLS from the Ministry of Science and Technology of China, the Strategic Priority Research Program of the Chinese Academy of Sciences (XDPB0301) to ZLS, the National Institutes of Health (NIAID R01AI110964), the USAID Emerging Pandemic Threats (EPT) PREDICT program to PD and ZLS, CAS Pioneer Hundred Talents Program to JC, NRF-CRP grant (NRF-CRP10-2012-05) to LFW and WIV "OneThree-Five" Strategic Program (WIV-135-TP1) to JC and ZLS. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing Interests: The authors have declared that no competing interests exist.

PLOS

Related Bats Articles from Brightsurf:

These masked singers are bats
Bats wear face masks, too. Bat researchers got lucky, observing wrinkle-faced bats in a lek, and copulating, for the first time.

Why do bats fly into walls?
Bats sometimes collide with large walls even though they detect these walls with their sonar system.

Vampire bats social distance when they get sick
A new paper in Behavioral Ecology finds that wild vampire bats that are sick spend less time near others from their community, which slows how quickly a disease will spread.

Why doesn't Ebola cause disease in bats, as it does in people?
A new study by researchers from The University of Texas Medical Branch at Galveston uncovered new information on why the Ebola virus can live within bats without causing them harm, while the same virus wreaks deadly havoc to people.

The genetic basis of bats' superpowers revealed
First six reference-quality bat genomes released and analysed

Bats offer clues to treating COVID-19
Bats carry many viruses, including COVID-19, without becoming ill. Biologists at the University of Rochester are studying the immune system of bats to find potential ways to ''mimic'' that system in humans.

A new social role for echolocation in bats that hunt together
To find prey in the dark, bats use echolocation. Some species, like Molossus molossus, may also search within hearing distance of their echolocating group members, sharing information about where food patches are located.

Coronaviruses and bats have been evolving together for millions of years
Scientists compared the different kinds of coronaviruses living in 36 bat species from the western Indian Ocean and nearby areas of Africa.

Bats depend on conspecifics when hunting above farmland
Common noctules -- one of the largest bat species native to Germany -- are searching for their fellows during their hunt for insects above farmland.

Tiny insects become 'visible' to bats when they swarm
Small insects that would normally be undetectable to bats using echolocation suddenly become detectable when they occur in large swarms.

Read More: Bats News and Bats Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.