SAN FRANCISCO (BLOOMBERG) - Facebook will begin removing fake claims and conspiracy theories about the Wuhan coronavirus, stepping up efforts to fight the spread of misinformation about a viral outbreak that has killed more than 200.

The spread of the virus, which has been declared a global emergency by the World Health Organisation, is the latest test of social networks' ability to rein in false and dangerous claims.

Facebook cited the drinking of bleach as one spurious cure claim that has been circulating, saying it will "start to remove content with false claims or conspiracy theories that have been flagged by leading global health organisations and local health authorities that could cause harm to people who believe them".

The company has an existing policy of removing content deemed a threat to users' physical well-being, and has used that policy in the past to remove vaccine-related misinformation, though in rare cases.

The novel coronavirus is taking on a life of its own on the Internet, once again putting United States-based social media companies on the defensive about their efforts to curb the spread of false information.

Researchers and journalists have documented a growing number of cases of misinformation about the virus, ranging from racist explanations for the disease's origin to false claims about miracle cures.

Aside from expanding its removal policy, Facebook is doing its usual fact-checking with independent third-party partners, notifying users who may have shared inaccurate prevention tips and disseminating verified advice.

The company is "conducting proactive sweeps to find and remove as much of" the misleading content as it can, wrote Mr Kang-Xing Jin, its head of health, and will block or restrict hashtags on Instagram that may be used to spread falsehoods.

Facebook is putting prompts and modules in its News Feed, designed to steer users to accurate information, and it is also taking guidance from the WHO.

"When people search for information related to the virus on Facebook or tap a related hashtag on Instagram, we will return a dedicated information module with credible information," Mr Jin wrote. Free advertising credits have been provided to health organisations looking to run coronavirus education campaigns on Facebook and Instagram.

The third prong to Facebook's response is a partnership with Harvard University's School of Public Health and Taiwan's National Tsing Hua University, which the company is providing with "aggregated and anonymised mobility data and high resolution population density maps to help inform their forecasting models".

The company may expand its academic partners, according to Mr Jin, though he warned that "not all of these steps are fully in place" and the roll-out of all of Facebook's measures will take time.

It is notable that Facebook has acknowledged misinformation relating to the virus outbreak as a real threat to users and not merely a nuisance. The step of actually removing misleading content and not just labelling it as such is a significant one for a company that has said it won't fact-check political advertising.

Still, information shared in private groups lies outside the reach of Facebook's fact-checking apparatus, and they have been known to incubate conspiracies on many different topics.

Twitter, Google and Youtube

Twitter's efforts in tackling the issue include directing users to reliable sources, prompting those who search for "coronavirus" to visit the Centres for Disease Control and Prevention website.

The company has not seen an uptick in disinformation since the coronavirus became a worldwide problem, a spokesman said. Twitter has a policy against people trying to mislead others with "deceptive activity".

Alphabet's Google has launched one of its so-called SOS Alerts for the coronavirus crisis, partnering with the WHO to issue news updates and resources to anyone searching about it. The alert will be the top thing anyone sees, offering safety tips and the latest updates from the WHO.

At YouTube, the company isn't yet taking any measures particular to the coronavirus, but it is battling the rush to hurried misinformation by showing short previews of text-based news articles about the outbreak in search results.