In a statement issued on Wednesday, the state-backed Wuhan Institute of Virology said “internet rumors” had “received close attention from all walks of life” and “caused great harm to our research staff on the front line of scientific research”.

It said its staff had been working around the clock since the end of 2019 to trace the source of the coronavirus and improve detection rates, but the conspiracies had “seriously interfered” with their efforts.

The institute has been accused of “artificially synthesizing” the coronavirus in one of its laboratories, it said. It also referred to other claims circulating online that the “patient zero” in the current outbreak was a graduate student from the institute, and that one of its researchers had also died after the virus “leaked”.

Conspiracy theories often prosper during epidemics, and have sprung up during recent outbreaks of Middle Eastern Respiratory Syndrome (MERS), avian flu and Ebola, said Adam Kamradt-Scott, an infectious diseases expert at the University of Sydney.

“If there is an infectious disease lab in a city where an outbreak starts, it usually gets the blame.”

Many of the rumors circulated domestically and overseas claim the coronavirus was engineered by local scientists and leaked, deliberately or by accident, in Wuhan where the virus was first detected and is the epicenter of the epidemic.

But another theory, debunked on Wednesday by the well-known rumor-busting website Snopes.com, connected the outbreak to the arrest last month of Harvard University professor Charles Lieber, who was accused of concealing ties with the Wuhan Institute of Technology.

The conspiracy theories have not stayed online. Republican Senator of Arkansas, Tom Cotton, told the Fox News channel this week that “we at least have to ask the question” whether the coronavirus originated in the Wuhan lab.

A team of 27 scientists published a statement in the Lancet medical journal on Tuesday condemning the conspiracy theories, which “do nothing but create fear, rumors and prejudice that jeopardize our global collaboration in the fight against this virus.”

They said scientists from around the world “overwhelmingly conclude that this coronavirus originated in wildlife”. The current consensus is that it emerged from a seafood market in Wuhan that also sold exotic wild animal products.

China usually cracks down heavily on “rumors”, and it even arrested Li Wenliang, a doctor who first disclosed the existence of a SARS-like disease in Wuhan at the end of last year and subsequently became its most prominent casualty.

But it has been unable to silence the vast number of outlandish claims circulating on social media channels.

Shanghai government newspaper Liberation Daily has published a regular round-up of misinformation, including allegations that large numbers of infected patients are coming to the city for treatment, and a claim the virus can be cured by strong curry.

Misinformation also prospered during the Severe Acute Respiratory Syndrome (SARS) outbreak in 2002-2003.

As well as conspiracy theories about the origins of the virus, rumors also spread across the country that frogs and newborn babies were suddenly speaking and giving advice about how to repel the disease, usually through firecrackers and incense sticks.

“Unfortunately it just seems to be that in addition to the epidemiological challenge we now also confront a simultaneous misinformation epidemic,” said Kamradt-Scott.