Researchers find that bats can spread new variation of SARS to humans

As if bats were not creepy enough.

More than a decade after Ralph Baric and a team of researchers from the Gillings School of Global Public Health started studying SARS, they discovered a new sequence of the virus that can jump from infected bats to humans without mutating.

Mainly found in Chinese horseshoe bats, the virus is not as pathogenic as SARS, Baric said, and for the virus to be passed from one human to another, some mutations may have to occur. There are still many questions waiting to be answered.

“We know it is capable of infecting all of the primary targets in the human lung that SARS can infect,” he said. “My gut feeling is that it would replicate and probably make someone sick."

The SARS, or severe acute respiratory syndrome, epidemic in 2003 started in China and infected more than 8,000 people, including one person in Chapel Hill, and killed nearly 800 people overall. Most of the people who died were over 60 years old. In 2004, SARS disappeared from humans, and many groups thought the virus was extinct. 

“It really isn’t extinct,” Baric said. “It’s really circulating through bats.”

Though how the virus in bats is transmitted to humans is unknown, Baric said he thinks it could be transmitted through contact with bat saliva and feces.

“With globalization, we have more and more areas that have never really seen people before but now there’s development,” said Vineet Menachery, a postdoctoral scholar working with Baric. “These bats don’t just go away — they can be found in buildings. So humans are getting into more contact with these species.”

Since the new sequence is 12 percent different from the original SARS virus, the current treatment for the SARS virus does not work on the new variant.

“It’s not just one virus in the reservoir, it’s this pool. Imagine this pool of closely related but different viruses, and each time one comes out of the pool, it’s like having a pool full of fish and a fish jumps out,” Baric said. “Trying to make vaccines for that pool becomes really difficult because you don’t know the boundaries of what you need to target.”

Virologist Mark Heise, who works with the team, said the virus is more complicated than he originally thought in 2004.

“When we first started working on SARS in 2004, we knew almost nothing about it,” he said. “We were afraid that if we used the wrong sources in the vaccine we would make the disease worse. Since then we have developed a much stronger picture.”

Helen Lazear, a microbiology and immunology assistant professor who studies diseases in bats, said researchers do not yet know why bats can harbor the number of diseases they do.

“We’re really in the early stages of learning about the epidemiology of bats,” she said. “There is a growing interest in bats and because of the growing interest, more people go out and look for viruses. The more they look, the more they find.”

Though many questions are left unanswered, Baric plans to continue his research to take a proactive approach to preventing future outbreaks.

“One of the major implications of our study is it now positions us to make better vaccines and have drugs that are much better and broader in their activities," he said. "So, if and when a future outbreak occurs, we will be in a position to move rapidly with intervention strategies."

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