Bats are known to harbour coronavirus, but scientists have yet to fully understand the new virus and how it leapt from animals to people.

The outbreak of a new virus linked to a wildlife market in central China is prompting renewed calls for enforcement of laws against the trade in and consumption of exotic species.

It’s also raising questions about how it could happen again after the lessons learnt from the 2002-03 outbreak of SARS, or Severe Acute Respiratory Syndrome, which was traced to consumption of wild animals in the southern city of Guangzhou.

In response to the crisis that has been centered in the big industrial city of Wuhan, China’s Agriculture Ministry issued an order earlier this week ordering tightened controls on trade in wildlife.

The New York-based Wildlife Conservation Society, meanwhile, appealed for an end to wildlife markets everywhere, not just in China.

Zoonotic diseases, or those contracted by humans that originated in other species, account for a large share of human infectious illnesses. Not all of them come from wildlife trade — rabies is endemic across many species and one of the biggest causes of death in the developing world. But mixing species of wild animals increases the risk of diseases mutating and growing more virulent as they spread in unregulated markets, experts say.

The emergence of such diseases is a “numbers game”, said Christian Walzer, executive director of the Wildlife Conservation Society’s health program.

“If these markets persist, and human consumption of illegal and unregulated wildlife persists, then the public will continue to face heightened risks from emerging new viruses, potentially more lethal,” he said.

The order issued by the Ministry of Agriculture and Rural Affairs, dated January 21, banned all shipments of wild animals out of Wuhan. It also called for stepped up inspections and raising public awareness about the risks of eating them.

Researchers have not yet announced a definitive source for this latest outbreak, which like many other viruses can infect multiple species.

One of the first measures taken by Wuhan authorities was to close down the Huanan Seafood Wholesale Market, where 41 of the first cases originated.

“That’s the big black box right now,” said Jon Epstein, an epidemiologist with the Ecohealth Alliance.

Bats are known to harbor coronaviruses, but scientists have yet to fully understand the new virus and how it leapt from animals to people.

Epstein said researchers suspect but haven’t proven that the Wuhan virus came from bats. Before it infected humans, it likely first jumped to an as yet unidentified mammal.

“There’s no plausible evidence to support snakes being involved with this virus,” Epstein said, referring to recent media speculation criticized by a recent article in Nature. Researchers don’t know which species exactly were sold in the Wuhan market, but Epstein said mammals commonly found in such markets — such as ferret badgers, raccoon dogs or civets — might be involved in the transmission of the new virus to people.

The crackdown on wildlife trafficking and sales persisted only about six months after the SARS outbreak faded in mid-2003, Walzer said.

“The solution is simple,” he said. “In the sense that we know where the problem is.”