Every New Yorker who has traveled and recently returned from China, Japan, Iran, Italy and South Korea have been told by the city's mayor to self-quarantine for 14 days as a coronavirus precaution.

Mayor Bill de Blasio made the recommendation at a press conference on Thursday where he struck a more concerned tone than in previous days and described the spread of the disease in New York City as 'unpredictable and worrisome'.

'Our level of concern is rising for sure... for all New Yorkers, if you have recently returned from one of the five countries, we're asking you to isolate yourself as a precaution for 14 days.

'Obviously, if you have symptoms then you need to get to care and testing,' he said.

He did not specify what he meant by 'recently' but he later referenced a 'time-frame'.

In most cases with the virus so far, the window of concern is 14 days.

Twenty-two people in New York State have now been diagnosed with the virus, including four in New York City.

A man in Long Island has been diagnosed with the virus.

Two men in New Jersey have also been diagnosed now, including one who has a significant 'nexus' to New York City.

CORONAVIRUS HOTSPOT COUNTRIES De Blasio is asking all New Yorkers who have recently returned from these countries to self-quarantine; China Japan South Korea Iran Italy Advertisement

Tests are now being carried out by the hundreds to determine who the infected people came into contact with and if they too now have the disease.

However Mayor de Blasio said the city cannot get enough tests fast enough to keep up.

The city has 1,000 tests currently, but with fast-growing numbers, de Blasio said the city urgently needs more.

'Each day we may tell you something new about how this disease.

'The community spread issue, we are seeking guidance from WHO and CDC, now that it's clearly established as a phenomenon here,' he said.

He went on to say that the 'big picture' is that 80 percent of people who have become infected have recovered.

The last 48 hours are sobering. Community spread is an entirely different ball game...We're all very sober right now about what tomorrow could bring or the day after that Bill de Blasio

'We need the ability to test and many people as possible as quickly as possible, we cannot do that without help from the federal government.

'We do not have the physical capacity we need. We need the FDA to speed up the approval of the test developed by private companies. We have to maximize our ability to do what we need to do,' he said.

'The last 48 hours are sobering.

'Community spread is an entirely different ball game.

'I don't want people to assume, I don't want people to overreact because this is going to be a day to day, hour by hour thing.

'Community spread is different. It makes it a lot harder for us to control the situation.

'We're all very sober right now about what tomorrow could bring or the day after that, he said.

Of the 22 cases in the state of New York, 17 are in Westchester and they have all been tied to a Manhattan attorney who was the second person to be diagnosed in the state.

NEW YORK STATE CORONAVIRUS CASES WESTCHESTER: 17 NEW YORK CITY: 4 LONG ISLAND: 1 Advertisement

Four people in New York City have the virus; the lawyer, a healthcare worker, a woman in her eighties and a man in his forties who has underlying lung issues due to smoking and vaping.

There is also one person in Nassau County, Long Island who has the disease. He is a 42-year-old man and he has been hospitalized.

Cuomo emphasized on Thursday that only a handful of the people who have been infected have had to be hospitalized and that all are getting better.

He said he was 'worried' about nursing homes and senior care facilities, but that for most residents the virus is like having the flu.

'When you know the facts, it's reassuring. On these facts, there is no reason for undue anxiety.'

Governor Andrew Cuomo said officials are now trying to track down people who came into contact with the new cases

De Blasio earlier pleaded with the CDC to send more test kits to New York City after confirming that a woman in her eighties and a man in his forties have tested positive.

'We are going to see more cases like this as community transmission becomes more common.

WHAT ARE THE CORONAVIRUS SYMPTOMS? The new virus, called COVID-19, is transmitted from person to person via droplets when an infected person breathes out, coughs or sneezes. It can also spread via contaminated surfaces such as door handles or railings. Coronavirus infections have a wide range of symptoms, including fever, coughing, shortness of breath and breathing difficulties. Mild cases can cause cold-like symptoms including a sore throat, headache, fever, cough or trouble breathing. Severe cases can cause pneumonia, severe acute respiratory illness, kidney failure and death. Symptoms may appear 2-14 days after exposure. Advertisement

'We want New Yorkers to be prepared and vigilant, not alarmed,' he said.

Doctors in Westchester are reporting not having the test kits needed to diagnose people.

'At this time no physician offices have the ability to test for COVID-19. The test can only be done by New York State or the Centers for Disease Control,' one school district, which has closed as a precaution, said in a statement.

Twenty-five other tests have been returned as negative, he said.

In Westchester, one thousand people will be told to self-quarantine after potentially coming into contact with a Manhattan lawyer and his family who all have the virus.

The lawyer, 50, is in the hospital. He is in a stable condition.

He gave the virus to his wife, 14-year-old daughter and 20-year-old son, and also gave it to the neighbor who drove him to the hospital.

He also spread it to a friend, who in turn passed it on to his wife, two sons and daughter.

MTA has stepped up disinfecting and cleaning subway stations, cars and buses amid the coronavirus outbreak

A woman in a mask gets on the New York City subway on Wednesday. There are now four confirmed cases of the virus in NYC

As a precaution, the children's schools have now been closed and eight people who work at his Manhattan law firm are being tested.

The total number of cases across the US is now 216 and 12 people have died.

Both de Blasio and New York Governor Andrew Cuomo said on Wednesday that despite the escalating number of cases, most New Yorkers have nothing to be afraid of.

'There are going to be dozens and dozens and dozens of people,' Cuomo said, adding that the only people the virus is truly dangerous for are those with underlying health issues or weakened immune systems.

There are now 216 cases of coronavirus in the US. Twelve people have died

The lawyer's movements in the last few weeks are illustrated above. People in New York City and New Rochelle and Westchester are going to be tested

The lawyer gave the virus to his own wife, son, daughter and neighbor. He has also given it to a friend who has now passed it on to his own family, bringing the total number of cases in New York to 11

Abroad students from SUNY and CUNY will be recalled on charter flights from China, Italy, Japan, Iran and South Korea. They will then be quarantined for 14 days when they return.

Subways are being cleaned routinely and taxi drivers are being urged to also clean their cabs more often than usual.

A small handful of schools and colleges which may have come into contact with the virus are closing as a precaution, but the city is by and large operating as usual.

No one in New York has died from the virus.

The only person to have been hospitalized is the lawyer. He had pneumonia before he contracted the virus.

The others are all quarantining at home. The lawyer's wife and daughter do not have any symptoms, and his son - who was exhibiting symptoms - is now improving.

In Washington state, where ten people have died, 22,000 people are being told to stay at home for fear of getting the virus.

California state also reported its first death on Wednesday. A 71-year-old man died on Wednesday after contracting the virus. He recently returned from a cruise ship which is now being stopped from docking, and is being kept 400 miles off the coast with passengers on board being tested for coronavirus.

Call 1-888-364-3065 for Information about coronavirus in New York

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MTA STEPS UP CLEANING ON NEW YORK CITY SUBWAYS TO PREVENT THE SPREAD OF CORONAVIRUS

HOW TO AVOID GERMS ON THE SUBWAY Immediately use alcohol-based hand sanitizer once getting off the subway or bus Wash your hands as soon as you can for at least 20 seconds using soap Avoid touching your eyes, nose and mouth before you've washed your hands Avoid using your phone Move away from other passengers who are coughing when possible Cover your sneeze or cough with a tissue and through it in the trash when possible Cough into your arm, not your hand, if you don't have a tissue Stay at home when you are sick If you are experiencing symptoms, call your healthcare provider before presenting yourself for treatment Avoid crowds and travel off-peak when possible Don't use your hand to push throug the turnstile Watch your bags and clean if they come into contact with the floor Don't eat or drink on the subway Advertisement

Subway cars, stations and trains within the New York City transit system will now be cleaned at least every 72 hours as part of a new policy established by the Metropolitan Transit Authority to combat the spread of the coronavirus.

The clean will focus on areas that are touched by commuters the most often, including subway turnstiles and handrails.

The MTA is said to be working with the National Centers for Disease Control (CDC) as it stockpiles its hygienic and cleaning supplies.

MTA Chairman and CEO Pat Foye said: 'We have enacted additional cleaning protocols designed to disinfect our stations, trains, buses, and Access-A-Ride vehicles. Working in coordination with the governor and state and federal health authorities, we continue to aggressively monitor the situation and take all necessary actions to ensure our system remains safe.'

As of Monday, bus and subway screens will also deploy a safety messages warning passengers of the potential spread of the coronavirus and advising the best ways to avoid germs. This guidance is offered in English, Chinese, Spanish, Russian and Korean.

'The safety of our customers and employees is our first priority as we continue to monitor the coronavirus,' added Patrick Warren, MTA Chief Safety Officer.

'The MTA is enhancing its cleaning regimen across all our operating agencies to ensure the system is safe for everyone. The best defense against COVID-19, according to the National Centers for Disease Control, continues to be good hygiene – frequent hand washing and self-care.'

The MTA has urged passengers to follow the recommendations from the CDC to prevent the spread of the virus and to avoid germs on the subway.