The 40,000 confirmed cases of coronavirus may only be the ‘tip of the iceberg’, the World Health Organisation (WHO) has warned.
Dr Tedros Ghebreyesus, director general at the WHO, urged other countries to ‘step up’ preparations because the epidemic may be more widespread than thought.
He pointed to a climbing number of cases in people who have never been to Wuhan, the outbreak’s epicentre, or China – where 99 per cent of cases have been recorded.
The warning comes after a businessman from Brighton caught the killer infection at a work conference in Singapore and is thought to have infected at least 11 others at a ski resort in the French Alps.
Figures show at least 900 people have died from the coronavirus across the world, with all but two of the deaths recorded in China.
Dr Ghebreyesus said on Twitter last night: ‘Coronavirus spread outside China appears to be slow now, but could accelerate.
‘Containment remains our objective, but all countries must use the window of opportunity created by the containment strategy to prepare for the virus’s possible arrival.
‘There have been some concerning instances of onward spread from people with no travel history to China.
‘The detection of a small number of cases may indicate more widespread transmission in other countries; in short, we may only be seeing the tip of the iceberg.
‘In an evolving public health emergency, all countries must step up efforts to prepare for #2019nCoV’s possible arrival and do their utmost to contain it should it arrive.’
He added: ‘This means lab capacity for rapid diagnosis, contact tracing and other tools in the public health arsenal.’
It comes after leading British scientists last week predicted there could be 10 times as many coronavirus cases than are currently reported.
The death toll in mainland China – the epicentre of the outbreak – has now reached 910, with 86 people dying on Friday alone.
There have been a further 450 cases in 27 other countries, including eight in Britain, and one death reported from the Philippines and Hong Kong, respectively.
But scientists warned the rapid spread of the virus across borders, coupled with its suspected two-week incubation period and the unreliability of testing methods, made it difficult to track.
Public Health England announced last week it would be possible to test more than 1,000 people a day for suspected coronavirus in laboratories across the UK from next week.
The diagnostic test currently used in London – where only 100 cases can be tested per day – will be available at 12 centres across England, Wales, Scotland and Northern Ireland to increase capacity and speed up results.
Professor Edmunds acknowledged that predicting the true scale of the outbreak involved a degree of ‘guesswork’, adding: ‘When there are very large numbers of cases it becomes very hard to confirm them all just because of manpower. Time will tell.’
He said the coming days would show whether the containment measures put in place by China had been effective.
Experts said it was too early to tell whether the declining number of cases in recent days was ‘good news’ because so much was unknown.
Roughly 3,900 new cases were reported worldwide on Wednesday, compared with 3,700 on Thursday and 3,200 on Friday.
It emerged last week that a businessman who became the first Briton to contract the virus fell ill after travelling to a business meeting at a luxury hotel in Singapore.
The unnamed man was one of 109 people who attended the meeting at the Grand Hyatt Singapore in January, where a number of other attendees also became ill.
When he tested positive after returning to the UK, he was taken to Guy’s and St Thomas’ infectious disease centre in London.
He is thought to have infected at least 11 others, who have all been rushed into quarantine at specialist hospitals.
It came amid warnings that health chiefs face a race against time to prevent the virus from hitting NHS hospitals already stretched dealing with winter illnesses.
Experts say rapid progress has been made developing a vaccine but it would not be available until the end of the year at the earliest.
Yesterday it emerged that Kaletra, a combination of two drugs used to treat HIV, is being trialled on coronavirus cases in China.
World health chiefs have warned hospital staff are at risk from a global shortage of protective masks.
Chinese scientists said pangolins, the scaly mammals, may have passed the coronavirus to humans after contracting it from bats.
There was an outpouring of grief in China yesterday after Li Wenliang, the whistleblowing doctor who tried to sound the alarm about the virus, was killed by it.