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Where and when did the infection start?

The source of the coronavirus is believed to be a seafood market in the central Chinese city of Wuhan. The city’s health commission said the infection broke out between December 12 and 29, with some of the patients employed at the market.

The animal source of the outbreak has not been identified but two recent research papers have pointed to bats and snakes as the possible culprits.

The market in Wuhan, now shut down, was home to stalls trading in many different animals, including snakes, marmots and poultry. These “wet” markets are popular in China as customers like to purchase their meat “warm” – that is, recently slaughtered.

Here’s how the virus can spread:

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How far has it spread?

While most people affected are in China, cases in this fast-moving outbreak have now been found in the United States, France, Australia, Hong Kong, Thailand, Malaysia, South Korea, Taiwan, Macau, Japan and the Philippines. Fourteen people are being tested in the United Kingdom.

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How quickly has it spread?

Since the outbreak in mid-December, cases have escalated at pace. Within a month, two people in China had died while about 40 cases were identified. Two weeks later, the death toll stands at 41 with more than 1,287 cases.

As of January 25, the virus has continued to spread internationally, with the United States recording a second infection. France and Singapore have confirmed three cases, while Nepal has identified its first and Thailand its fifth.

Despite the speed and spread of the virus, experts have been surprised that the World Health Organisation (WHO) has not declared a global health crisis, which would see emergency measures put in place. The organisation said it was “too early” to do so.

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How many people are infected?

Currently, there are more than 1,300 known cases.

How many people have died?

Forty-one people have died. Most experts expect this number to rise and there is concern that China is not being honest about the spread and potential impact of the virus.

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Is there a vaccine?

No. And some pharmaceutical experts have warned that a vaccine could be years in the making. Beijing was quick to share what it knew about the virus’s genetic code, which means researchers in the US and China have already begun working on a vaccine. However, any vaccine may not be available for up to a year and priority would go to health workers most at risk of contracting the virus.

Professor Robin Shattock, from Imperial College London, said his team had “two vaccine candidates” developed from the genetic sequence of coronavirus provided by Chinese scientists, and some British experts are confident that a vaccine could be available within weeks.

Prof Shattock told Radio 4’s Today programme the vaccines would be ready for use in “animal models” by the middle of next month and they were ready to “rapidly move those into human studies” if required.

For now, it is a case of containment. China has started building a hospital to treat only patients with the virus which it hopes to finish within days.

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Is this virus like Sars?

Yes and no. Like all the devastating disease outbreaks of recent years, including HIV and Ebola, coronaviruses emerge from animals – in the case of Sars (severe acute respiratory syndrome) the disease jumped from bats to civet cats, a delicacy in parts of China, to humans. And in Mers (Middle East respiratory syndrome) the disease leaped from bats to camels to humans.

Sars, first reported in China in 2002, spread to 27 countries, infecting around 8,000 people and killing 700. It spread quickly but then appeared to run itself out.

Mers on the other hand, is more tenacious. It first emerged in 2012 in Jordan and about 2,500 cases of the disease have been identified so far. It is more deadly than Sars, and has claimed about 850 lives in total.

Like Sars, and unlike Mers, this coronavirus presents symptoms which make it easier to identify.

There is no vaccine for Sars or Mers that is both safe and effective in humans.

China is keen to avoid the international anger it provoked in its slow response to Sars. At the time it was accused of covering up the outbreak.

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Is the virus in the UK?

So far, 14 people tested for coronavirus in Britain have been given the all-clear but checks are still ongoing on “a handful” of new cases, and an expert at Public Health England said it was “highly likely” the virus would reach the UK. On Friday, the first cases were confirmed in Europe as three patients were identified in France.

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