It appears the longstanding and deadly mystery surrounding the origin of the SARS virus has been solved. Virologists have been scouring China for clues since the 2002 outbreak, finally stumbling upon a cave in Yunnan where they believe with near certainty the contagion originated. Only a few questions — very major ones — remain unanswered.
Writing in the journal PLoS Pathogens, scientists Shi Zhengli and Cui Jie of the Wuhan Institute of Virology, explained they singled out bats while conducting their SARS origin research. Specifically, they focused on horseshoe bats, which Australian scientists linked to the virus in 2013. Once the two virologists arrived in Yunnan, they spent five years painstakingly observing populations and collecting tissue and fecal samples.
After surveying dozens of locations, their research team identified one cave in particular, where they found "a single population of horseshoe bats [harboring] virus strains with all the genetic building blocks of the one that jumped to humans in 2002," Nature reports. Out of caution, the location of the cave has not been made public, although researchers say it is less than one kilometer from the nearest town.
Shi and Cui now believe the SARS virus originated in this group of bats, then spread to other animals — such as civets — before jumping to humans. And that is where the mystery remains. Professor Tu Changchu, who peer reviewed the SARS bat origin research, told Nature the results are 99 percent conclusive. He stated that if a method of animal-to-human transmission could have been found, "the evidence would be perfect".
But that crucial link has yet to be discovered. When SARS — severe acute respiratory syndrome — first emerged in 2002, scientists suspected several animals including bats, civets, monkeys and badgers as being potential culprits. Once communicable in people, the virus infected at least 8,700 people worldwide, proving fatal in 775 cases.
One other major question hangs in the air — How did a virus originate in Yunnan, affect no one in the province, and yet still travel all the way to Guangdong province, where the first infections arose? Tu, the virologist peer reviewer commented that this conundrum "has puzzled me a long time". Thanks to the work of Shi, Cui and their research assistants, the world is one step closer to answering the riddle of SARS and similar viruses. But the key mechanism explaining how and when such infections jump to humans remains an open question.
Editor's note: Special thanks to GoKunming user 'jiangwu' for first bringing our attention to this story in the Forums.
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