Scientists track link between wildlife and COVID-19 outbreak

The novel coronavirus responsible for the ongoing OVID-19 pandemic may have originated with wildlife and then infected people, scientists say.

The researchers from the University of Southern California (USC) in the US say the COVID-19 pandemic and additional outbreaks over the last decade are linked to wild life.

"Humans are increasing the odds of disease happening as we move into wild areas and catch wild animals," said Paula Cannon, a professor at USC.

"We created the circumstances where it was only a matter of time until something like this happens, and it will only be a matter of time before it happens again," Cannon said in a statement.

Scientists are not certain how this latest outbreak began and spread, but they believe the coronavirus likely originated in populations of horseshoe bats.

Cannon said there's strong evidence for this hypothesis and it's the best explanation at present.

They pinpointed a marketplace in Wuhan, China, as the epicentre for the outbreak, where the virus may have first infected humans and then spread around the world.

While the market has been identified as a seafood market, live animals were also sold there -- some as pets or for food, the resaerchers said.

This close proximity with infected animals enabled the virus's transmission to humans, they said.

Similar outbreaks have occurred before, such as with MERS and SARS several years ago, according to the researchers.

Evidence suggests that MERS spread from bats to camels to people, while SARS likely occurred as a result of transmission from bats to civet cats to humans, Cannon said.

Bats are also believed to be the original source of Ebola virus outbreaks that infected people in Africa from 2014 to 2016, and in 1976, the researchers said.

Scientists have found very strong genetic clues that COVID-19 originated with bats, they said.

Cannon said that's because part of the coronavirus's genetic code looks very similar to viruses found in bats.

There's also a signature resembling pangolin viruses, but whether pangolins had a direct role in transmission or were also victims of transmission from bats is unclear, she said.

"There are hundreds of coronaviruses, and a large number of them are found in bats," Cannon said.

"Based on what happened previously with SARS and MERS and now COVID-19, scientists are very concerned that other viruses will one day make the jump from bats to humans.

"It may be once in 100 years that the alchemy is right to infect humans, but when it does, it takes off like wildfire," she said.