Here's a look at what you need to know about the new virus

https://www.livescience.com/new-china-coronavirus-faq.html

A newly identified coronavirus called 2019-nCoV has been spreading in China, and has now reached multiple other countries. Here's a look at what you need to know. 

Update on Friday, Jan. 31 (ET):

— Starting on Sunday, Feb. 2, U.S. citizens, permanent residents and immediate family who have been in the Hubei province in China will be subjected to a mandatory two-week quarantine, officials announced on Friday (Jan. 31). 

—"Foreign nationals" who have traveled to China in the past 14 days won't be allowed in the U.S., they said. If Americans visited any other part of China, they will be screened at airports and asked to self-quarantine for 14 days.

— The 195 Americans who were flown from Wuhan to the U.S. will also be quarantined for 14 days, the Centers for Disease Control and Prevention (CDC) announced earlier today (Jan. 31).

—There are now 9,783 individuals in mainland China (and a global total of 9,926) who have been confirmed to have the new coronavirus, according to the Johns Hopkins virus dashboard.   

—There are now 213 deaths linked to the virus.

—The World Health Organization (WHO) has declared that the new coronavirus outbreak is a public health emergency of international concern, officials announced on Thursday.

— The U.S. issued a "Level 4" travel advisory — the highest level of warning — to not travel to China at all.

—The first instance of person-to-person transmission of the virus in the U.S. has now been reported in Illinois, the sixth person in the U.S. to be confirmed to have the new coronavirus, the Centers for Disease Control and Prevention (CDC) reported Thursday afternoon. 

—On Jan. 30, WHO proposed calling the disease "2019-nCoV acute respiratory disease." The final decision on the virus' official name will be made by International Committee on Taxonomy of Viruses.

—The virus seems to be spreading overseas, outside of China, to people who haven't visited the region, with cases popping up in Germany, Japan, Taiwan and Vietnam, The New York Times reported. This indicates more than a limited ability for person-to-person transmission. 

—Johns Hopkins University has set up a live dashboard showing the spread of the virus. For more about the dashboard, check out this analysis on our sister site Tom's Guide.

See below for up-to-date information on everything you need to know about the spreading coronavirus. 

What is a coronavirus?

Coronaviruses are a large family of viruses that can cause respiratory illnesses such as the common cold, according to the Centers for Disease Control and Prevention (CDC). Most people get infected with coronaviruses at one point in their lives, but symptoms are typically mild to moderate. In some cases, the viruses can cause lower-respiratory tract illnesses such as pneumonia and bronchitis. 

These viruses are common amongst animals worldwide, but only a handful of them are known to affect humans. Rarely, coronaviruses can evolve and spread from animals to humans. This is what happened with the coronaviruses known as the Middle East respiratory syndrome coronavirus (MERS-CoV) and the severe acute respiratory syndrome coronavirus (SARS-Cov), both of which are known to cause more severe symptoms.

Where did the new virus come from?

Since the virus first popped up in Wuhan in people who had visited a local seafood and animal market (called the Huanan seafood market), officials could only say it likely hopped from an animal to humans. In a new study, however, the researchers compared the 2019-nCoV genetic sequence with those in a library of viral sequences, and found that the most closely related viruses were two coronaviruses that originated in bats; both of those coronaviruses shared 88% of their genetic sequence with that of 2019-nCoV.

Based on these results, the authors said the 2019-nCoV likely originated in bats. However, no bats were sold at the Huanan seafood market, which suggests that another yet-to-be-identified animal acted as a steppingstone of sorts to transmit the virus to humans.

A previous study suggested snakes, which were sold at the Huanan seafood market, as a possible source of 2019-nCoV. However, some experts have criticized the study, saying it's unclear if coronaviruses can infect snakes. 

Does the virus have an official name?

No, neither the virus nor the disease it causes have official names yet. On Jan. 30, WHO proposed calling the disease "2019-nCoV acute respiratory disease," and the virus "2019-nCoV." (In these names, the "‘n" stands for novel and "CoV" is for coronavirus.) WHO will need to seek approval for the name from the World Organization for Animal Health (OIE) and Food and Agriculture Organization (FAO). The final decision on the virus' official name will be made by the International Committee on Taxonomy of Viruses, according to WHO.

In a report published on Jan. 29, researchers in China referred to the disease as novel coronavirus (2019-nCoV)–infected pneumonia, or NCIP.  

WHO discourages naming new viruses after geographic locations, people, species or classes of animals or foods, according to the organization's Best Practices for the Naming of New Human Infectious Diseases. Rather, WHO encourages use of descriptive terms of a disease, such as "respiratory disease" and "neurologic syndrome," as well as "severe" or "progressive." The organization also says that if a pathogen is known, it should be used as part of the disease's name.

Can the virus spread between people?

Yes, the virus is reportedly spreading from person-to-person in many parts of China, and in some other countries, according to the CDC. On Jan. 30, the CDC identified the first case of person-to-person spread in the United States. 

In terms of how one would catch the virus, the CDC says that human coronaviruses are most commonly spread between an infected person and others via: 

—the air (from viral particles from a cough or sneeze); 

—close personal contact (touching or shaking hands); 

—an object or surface with viral particles on it (then touching your mouth, nose or eyes before washing your hands);

 —and rarely from fecal contamination.  

How would this virus cause a pandemic?

In order for this virus, or any, to lead to a pandemic in humans, it needs to do three things: efficiently infect humans, replicate in humans and then spread easily among humans, Live Science previously reported. Right now, its unclear how easily the virus spreads from person to person.

To determine how easily the virus spreads, scientists will need to calculate what's known as the "basic reproduction number, or R0 (pronounced R-nought.) This is an estimate of the average number of people who catch the virus from a single infected person, Live science previously reported. A study published Jan. 29 in the New England Journal of Medicine (NEJM) estimated an R0 value for the new coronavirus to be 2.2, meaning each infected person has been spreading the virus to an average of 2.2 people. This is similar to previous estimates, which have placed the R0 value between 2 and 3. (For comparison, SARS initially had an R0 of around 3, before public health measures brought it down to less than 1.)

In general, a virus will continue to spread if it has an R value of greater than 1, and so public health measures to stem the outbreak should aim to reduce R0 to less than one, the authors of the NEJM paper said.

The CDC says outbreaks of new viruses are always concerning. However, the agency says the immediate risk to the American public remains low, given the small number of cases and limited spread of the virus here.

Still, an individual's risk of infection "depends on exposure," the CDC said. Some people, including health care workers and those with close contacts infected with 2019-nCoV, are at increased risk of infection, the agency said.

On Jan. 30, the World Health Organization (WHO) declared that the new coronavirus outbreak is a public health emergency of international concern. The main reason for the declaration is concern that the virus could spread to countries with weaker health systems, WHO said.

How does the virus compare to SARS and MERS?

MERS and SARS have both been known to cause severe symptoms in people. It's unclear how the new coronavirus will compare in severity, as it has caused severe symptoms and death in some patients while causing only mild illness in others, according to the CDC. All three of the coronaviruses can be transmitted between humans through close contact. 

MERS, which was transmitted from touching infected camels or consuming their meat or milk, was first reported in 2012 in Saudi Arabia and has mostly been contained in the Arabian Peninsula, according to NPR. SARS was first reported in 2002 in southern China (no new cases have been reported since 2004) and is thought to have spread from bats that infected civets. The new coronavirus was likely transmitted from touching or eating an infected animal in Wuhan. 

During the SARS outbreak, the virus killed about 1 in 10 people who were infected. The death rate from 2019-nCoV isn't yet known. In the beginning of an outbreak, the initial cases that are identified "skew to the severe," which may make the mortality rate seem higher than it is, Alex Azar, secretary of the U.S. Department of Health and Homeland Security (HHS), said during a news briefing on Tuesday (Jan. 28). The mortality rate may drop as more mild cases are identified, Azar said.

Currently, most of the patients who have died from the infection have been older than 60 and have had preexisting conditions. 

What are the symptoms of the new coronavirus and how do you treat it?

Symptoms of the new coronavirus include fever, cough and difficulty breathing, according to the CDC. It's estimated that symptoms may appear as soon as two days or as long as 14 days after exposure, the CDC said. The NEJM study published on Jan. 29 estimated that, on average, people show symptoms about five days after they are infected.

There are no specific treatments for coronavirus infections and most people will recover on their own, according to the CDC. So treatment involves rest and medication to relieve symptoms. A humidifier or hot shower can help to relieve a sore throat and cough. If you are mildly sick, you should drink a lot of fluids and rest but if you are worried about your symptoms, you should see a healthcare provider, they wrote. (This is advice for all coronaviruses, not specifically aimed toward the new virus).

There is no vaccine for the new coronavirus, but researchers at the U.S. National Institutes of Health confirmed they were in preliminary stages of developing one. Officials plan to launch a phase 1 clinical trial of a potential vaccine within the next three months,  Dr. Anthony Fauci, Director of the National Institute of Allergy and Infectious Diseases, said in a news conference on Jan. 28.

Researchers are also working on gathering samples of the virus  to design a therapy that will train patients' immune cells to detect and destroy the virus, Facui said. 

What is being done to stop the spread of the coronavirus?

The Chinese government put Wuhan and many other nearby cities on "lockdown," meaning people are not allowed in or out of the area, according to The New York Times. 

The governments of both Taiwan and Hong Kong have said they would not allow in anyone from the Hubei Province (where Wuhan is located).

Major airports in the U.S. are conducting screenings to try to check for symptoms of the virus. On Jan. 28, CDC officials announced that 15 additional U.S. airports will begin screening travelers for the virus, bringing the total number of airports conducting screening in the U.S. to 20. The CDC also recommends that Americans avoid all nonessential travel to China.

Nearly 200 Americans have been evacuated from Wuhan and will be monitored for 14 days for signs of infection, according to CNN.

As of Sunday (Jan. 26), the Chinese government had banned the sale of wildlife in markets, restaurants and online. 

"The banning of such sales will help end the possibility of future outbreaks of zoonotic diseases, such as the Wuhan coronavirus," Christian Walzer, chief global veterinarian at for the Wildlife Conservation Society, said in a WCS statement. "We learned this lesson with the outbreak of another zoonotic disease, SARS, in 2002. The pattern will keep repeating itself until we ban, not only in China, but in other countries, the sale of wildlife, specifically for food and in food markets," Walzer added.

How can people protect themselves and others?

the virus, according to the CDC. In general, the CDC recommends the following to prevent the spread of respiratory viruses: Wash your hands often with soap and water for at least 20 seconds; avoid touching your eyes, nose, and mouth with unwashed hands; avoid close contact with people who are sick; stay home when you are sick and clean and disinfect frequently touched objects and surfaces.

If traveling to China, you should avoid contact with sick people, avoid dead or alive animals, animal markets or products that come from animals such as uncooked meat, the CDC said. 

People who traveled to China and became sick with fever, cough or difficulty breathing within the following two weeks should seek medical care right away, and call ahead to inform medical staff about their recent travel, the CDC said.

Jeanna Bryner, Rachael Rettner, Yasemin Saplakoglu and Nicoletta Lanese contributed reporting.