Hundreds more people have been infected by a new mystery virus than the official figures suggest, scientists have said.
There have been 45 confirmed cases of coronavirus, with five people in a serious condition, the Wuhan Municipal Health Commission said on Saturday.
Two people have died of pneumonia in Wuhan following the outbreak, Chinese officials have confirmed.
But a report published by the London Imperial College’s MRC Centre for Global Infectious Disease Analysis asserted there are likely “substantially more cases” of the new coronavirus than have been formally reported.
A summary of the report on the centre’s website says its baseline scenario estimates that there would be 1,723 cases showing onset of related symptoms by January 12.
Neil Ferguson, a professor working with the team at Imperial College told the BBC: “I am substantially more concerned than I was a week ago”.
Size of Wuhan outbreak of a novel #coronavirus estimated from the three cases detected outside China: Likely to be over 1000 cases. @imperialcollege @mrc_outbreaks report released today— MRC Centre for Global Infectious Disease Analysis (@MRC_Outbreak) January 17, 2020
🔰 https://t.co/7A77NXZ3iw pic.twitter.com/u0dUnMs9hA
The original outbreak of the virus is believed to trace back to a seafood market in Wuhan, but authorities say some patients they have identified deny having any exposure to this market. The market has been completely closed since January 1.
With a population of 19m people, Wuhan is one of China’s biggest cities and is also home to a major airport, through which an estimated 3,400 travel internationally every day.
Thailand reported two cases of the coronavirus from Chinese travellers from Wuhan this week, while Japan confirmed one case involving a Japanese national who traveled to Wuhan.
“That caused me to worry,” Ferguson told the BBC.
“For Wuhan to have exported three cases to other countries would imply there would have to be many more cases than have been reported.”
Memories remain fresh in Asia of a 2002/03 outbreak of Severe Acute Respiratory Syndrome (SARS), which emerged in China and killed nearly 800 people worldwide.
Officials in China and the World Health Organisation (WHO) have confirmed the virus is a strand of coronavirus, which at their weakest can cause mild cold-like symptoms, but at their most dangerous can lead to SARS.
Health officials say the new virus discovered in Wuhan does not appear to be as lethal as SARIS but admit they still know little about it, including its origins or how easily it can be transmitted from person to person.
Preliminary analysis of the novel coronavirus (in red) believed to be responsible for an outbreak of pneumonia in Wuhan, China shows it's closely related to SARS CoV. https://t.co/Vf6U2W4oYR pic.twitter.com/3WbFpQ02Pc— EcoHealth Alliance (@EcoHealthNYC) January 11, 2020
The outbreak comes just ahead of celebrations of the Lunar New Year – an event that sees millions of people in China travel from major cities such as Wuhan to their hometowns both within the country and abroad.
At least six countries in Asia also have started screening incoming airline passengers from central China, including Thailand and Japan, which both have reported cases of the disease in people who had come from Wuhan.
The US announced Friday it would begin screening passengers at three major airports arriving on flights from Wuhan.
Australia, which saw about 1.4 million short-term arrivals from China last year, is not planning any special screenings for now.
The WHO has said it advises against any travel or trade restrictions on China.
This article originally appeared on HuffPost.