Conspiracy theories suggesting that the novel coronavirus originated in a laboratory in Wuhan, Central China's Hubei province, have no basis in fact, the head of the lab told Reuters, adding that there were "still no answers" as to the origin of the virus.

The rumors claims that the novel coronavirus, now responsible for more than 200,000 deaths worldwide, was synthesized by the Wuhan Institute of Virology, or WIV, based in the city where the disease was first identified.

Yuan Zhiming, professor at WIV and the director of its National Biosafety Laboratory, said "malicious" claims about the lab had been "pulled out of thin air" and contradicted all available evidence.

"The WIV does not have the intention and the ability to design and construct a new coronavirus," he said in written responses to questions from Reuters. "Moreover, there is no information within the SARS-CoV-2 genome indicating it was manmade."

"More than 70 percent of emerging infectious diseases originated from animals, especially wild animals," Yuan said.

"In recent years, we have seen increasing risks posed by close contact between humans and wild animals, with global climate change and the continuous expansion of human activities," he said.

All seven known human coronaviruses have origins in bats, mice or domestic animals, scientists say.

Yuan also rejected theories that the lab had accidentally released a coronavirus it had harvested from bats for research purposes, saying the lab's biosecurity procedures were strictly enforced.

"High-level biosafety labs have sophisticated protective facilities and strict measures to ensure the safety of laboratory staff and protect the environment from contamination," he said.

Experts overwhelmingly say analysis of the new coronavirus's genome rules out the possibility that it was engineered by humans, as some commentators have suggested, according to The Associated Press.

Nor is it likely that the virus emerged from a negligent laboratory in Wuhan, they say. "I would put it on a list of 1,000 different scenarios," said Nathan Grubaugh of Yale University, who studies the epidemiology of microbial disease.

Scientists say the virus arose naturally in bats.

Agencies