A mysterious new virus is sweeping through parts of Asia, infecting more than 200 people since it was first detected in Wuhan, China, in December.

The new illness is believed to have originated from a seafood market in Wuhan, a densely populated central Chinese city home to about 11 million people. It has been dubbed the Wuhan virus, or the 2019-nCoV, and is considered to a coronavirus, which causes cold-like symptoms and is considered "zoonotic" and can be transmitted between animals and humans.

According to the World Health Organization, signs of coronavirus infection include respiratory symptoms, fever, cough, and breathing difficulties. In more severe cases, the infection can cause pneumonia, kidney failure, and even death.

A microscopic view of a coronavirus, whose name comes from the crown shape surrounding the virus. BSIP/UIG Via Getty Images

The virus is considered to be a "novel coronavirus" because it is a new strain that had not previously been identified in humans. There are no vaccinations for the disease, though the WHO has published interim guidelines for ways countries can prepare for this virus, including monitoring sick people, treating and quarantining patients, and communicating with the public about the spread of infection.

As of Tuesday, at least four people in Wuhan had died from the virus, according to local authorities. The virus has also spread to other Chinese cities, including Beijing and Shenzhen, as well as to South Korea, Thailand, and Japan. Several unconfirmed cases have also been reported in the UK and Australia.

Authorities by late Monday had confirmed 217 cases of infection in China, according to Reuters. Of that number, 198 people were infected in Wuhan alone, which was triple the number of cases disclosed the previous day by Chinese authorities. On Tuesday, Wuhan health authorities said dozens of patients remained in hospitals with the virus, some critically ill and all under quarantine.

But China's handling of 2003's SARS epidemic has sparked concerns among observers of another pandemic and state-sanctioned cover-up.

Fears of another SARS-like outbreak

Health workers in full protective clothing during the clean-up operation at Amoy Gardens where more than 200 residents were infected with the SARS virus in 2003 in Hong Kong. Christian Keenan/Getty Images

Fears of another global outbreak stem from China's handling of the deadly SARS virus in the early 2000s.

Experts have noted similarities between the Wuhan virus and the virus that causes severe acute respiratory syndrome, which reached epidemic proportions from November 2002 to July 2003. The epidemic consisted of 8,098 cases of the disease and 774 deaths across at least 30 countries.

The outbreak of the illness was traced to China's southeastern Guangdong province and was genetically traced to have spread through bats.

During the initial stages of the outbreak, the Chinese government concealed information from the public, limiting mitigation efforts and exacerbating the spread of disease. The country also had no government agencies in place at the time to deal with a public-health emergency.

The government did not inform the WHO of the outbreak until February 2003, allowing the disease to flourish.

According to The Sydney Morning Herald, doctors in Beijing were ordered by authorities to hide SARS patients from WHO officials during inspections.

The tight-lipped response from the Chinese government on the disease had both political and economic motivations, meant to reduce public panic and keep the status quo within the country. Taiwanese legislators even accused China of unleashing the virus as part of a biological warfare campaign, though no conclusive evidence has been found, according to Reuters.

A Chinese doctor named Jiang Yanyong eventually exposed China's attempted cover-up of the disease, earning him a human-rights award that he was barred from traveling to collect in the US. He was also reportedly taken into Chinese military custody before being released in 2014.

China eventually did apologize in 2003 for its slow reporting of the outbreak and promised to establish a national medical emergency mechanism.

Chinese authorities have jumped in to control the spread of information on the Wuhan virus

Medical staff members carrying a patient into the Jinyintan hospital, where patients infected by a mysterious SARS-like virus were being treated, in Wuhan in China's central Hubei province on Saturday. STR/AFP via Getty Images

On Sunday, China's National Health Commission said in its first public statement on the outbreak that an epidemic of the disease was "still preventable and controllable."

On Monday, the health body was forced to acknowledge that the disease was able to spread person-to-person and that cases of infection were reported by people who never set foot in Wuhan.

"Currently, it can be said it is affirmative that there is the phenomenon of human-to-human transmission," Zhong Nanshan, a scientist at the National Health Commission, said in an interview on the Chinese state broadcaster CCTV. He added that the spread of the deadly infection was "climbing," though he said the "death rate at the moment is not so representative."

Chinese leaders have also spoken out on the disease, promising to share pertinent information with the public quickly.

Chinese Premier Li Keqiang on Monday pledged that the government would "adhere to openness and transparency" and would "release authoritative information" on the virus "in a unified manner."

Chinese President Xi Jinping also gave a statement on the health crisis, saying it was necessary to "release information on the epidemic in a timely manner and deepen international cooperation."

A waiting area for a train to Wuhan at the Beijing West Railway Station. Reuters

Despite this, observers are still skeptical about China's commitment to speaking the truth, as China has also been known to distort data and enforce strict censorship in reference to information it shares with the public.

Reuters' China correspondent Cate Cadell tweeted that several people she had spoken with reported being tracked by Chinese authorities for posting information about sick relatives or friends on social media or for talking to members of the press.

According to Reuters, users of the microblogging platform Weibo have complained of lacking access to clear guidance from the government on preventing the spread of disease.

Scientists at Imperial College London working in collaboration with the WHO suggest the actual number of people infected by the virus may be anywhere from 996 to 2,298, which are figures significantly higher than those released by the Chinese government so far.

There are also concerns that China is downplaying the severity of the virus ahead of China's Lunar New Year holiday, often described as the "largest human migration in the world," which could accelerate the crisis rapidly as millions prepare to travel to the country.

China's mistakes will be tested as it faces a new outbreak

Medical staff near the Jinyintan hospital in Wuhan, which houses patients with the Wuhan coronavirus, on January 10. Reuters

The world is closely watching the Chinese government as it responds to the spread of its newest coronavirus in the wake of its SARS crisis.

Experts have noted that China has learned much from the SARS crisis, including the need for coordinated response.

But news about the virus has spread across social media, raising pressure on the Chinese government to increase transparency.

On Sunday, the journalist David Paulk posted a video of medics in hazmat suits scanning dozens of plane passengers for the symptoms of the virus, stoking fears of a pandemic.

Three US airports have also begun screening passengers for the disease, as have airports in Singapore and Hong Kong, according to the BBC.

"The government seems to have learned that in an era of the Internet and cell phones, a complete information blackout is not only impossible but also counterproductive," Yanzhong Huang, who published a report on the SARS epidemic and its aftermath in China, wrote in 2004.