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Mystery Coronavirus from China: What to Know

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This story was updated Jan. 23, 2020 with information from a WHO press conference. 

Jan. 22, 2020 -- The public should be paying attention, but not panicking about a new virus that has recently spread from Wuhan, China, to several other countries, including the U.S., public health experts say. The virus, known as a coronavirus, has now reportedly killed 17 and sickened 584, including a man in Washington state -- though it is likely to have infected many more. Fears over its spread led Chinese officials to announce that they will temporarily shut down public transportation out of the city of 11 million people, starting Jan. 23. They are putting similar restrictions on several smaller cities outside of Wuhan as well. 

The WHO Thursday voted not to declare the virus a “public health emergency of international concern.” The vast majority of the cases are still concentrated in China, WHO officials said, and there is no evidence of spread in any other countries where it's been diagnosed.

“I think we should be a little concerned, but not overly so,” says Jim Le Duc, PhD, director of the Galveston National Laboratory at the University of Texas Medical Branch. The warning flags, he says, are the virus’s ability to kill, the fact that it can be transmitted from person to person, and its newness -- meaning no one has had time to build up immunity.

It has also arrived during flu season, when there are lots of other respiratory viruses that could make it hard to identify, and just before the Chinese Lunar New Year, when many people will be traveling to celebrate with their families and could spread the disease, he says. U.S. officials will force all travelers from that part of China to come in through certain airports and be screened for symptoms of the disease.

There are still many questions about the new virus, such as where it came from, how it passed to people (it is usually found in mammals), whether people can be contagious without showing signs of the disease, and how best to treat it, says W. Ian Lipkin, a professor of epidemiology at the Mailman School of Public Health at Columbia University in New York.

WebMD interviewed a half-dozen infectious disease experts and also took part in conferences by the CDC and WHO to understand what we know so far about the new virus.

What is a coronavirus?

The virus belongs to the same family of coronaviruses that includes the common cold, but also severe acute respiratory syndrome, or SARS. In 2002-2003, a SARS epidemic sickened more than 8,000 people worldwide -- particularly in China, Taiwan, Singapore, and Canada -- and killed about 10% of its victims.

The main difference between the two outbreaks, Le Duc and others say, is that the Chinese government is being far more collegial and open about the Wuhan coronavirus now than it was about SARS. The government has been releasing updated figures about the number of those sickened and last week released a genetic sequence of the new virus, allowing scientists around the world to study it.

“We’re certainly not out of the woods. There’s lots of reasons to be concerned,” Le Duc says, “But we’re not being blindsided as we were previously.”

Roughly one-quarter of those reported illnesses are considered severe, the WHO reported. Because some patients are still quite ill and could die, and because it is not yet clear how many people might have mild cases of the disease, it is not yet possible to know the virus’ death rate. SARS killed roughly 10 percent of its victims, and MERS about one-third, WHO figures show.

Of the 17 people who have died during the current outbreak, most had underlying health conditions such as high blood pressure, diabetes or heart disease, said WHO Director General Tedros Adhanom Ghebreyesus.

What are the symptoms of a coronavirus?

According to the CDC, a coronavirus usually causes a mild to moderate respiratory illness similar to the common cold. It usually lasts for just a few days.

Symptoms include:

Severe cases affect the lower respiratory tract and can cause pneumonia or bronchitis. These cases are more common in people with heart or lung disease or with weakened immune systems, as well as in very young children and seniors.

How quickly is it spreading?

“The speed at which we’re seeing this transmit to other countries suggests that the actual number of people in Wuhan who are able to transmit the virus is probably in the thousands at this point, which is one of the most concerning things,” says Michael Mina, an epidemiologist at the Harvard School of Public Health.

So far, the virus has been passed from Wuhan to several other parts of China. There are also cases in Japan, South Korea, Singapore, Thailand, Vietnam and the U.S.

The large outbreak and quick spread could mean that many more people are getting the infection but don’t have symptoms, Mina says. If only six people have died out of the 1,500 to 2,000 who are believed to have been sickened from the disease, then it is not as lethal as SARS and a similar illness called Middle East respiratory virus, he notes.

The American who fell ill, a man from Snohomish County, WA, north of Seattle, was immediately suspected of having the virus because of his travel history. A specimen sent overnight to the CDC confirmed his illness late Monday, and it was announced to the public Tuesday.

Mina says being able to rapidly test for the Wuhan coronavirus bodes well for containing an epidemic. “It gives some hope that we may be able to control this, because we were able to roll out a diagnostic so quickly,” he says. “Although there are a lot of unknowns, this has probably been the fastest response to date of any epidemic.”

What happened in Washington state?

The Washington man, believed to be in his 30s, apparently traveled back from Wuhan on Jan. 15 and started feeling ill 4 days later. It’s not clear whether he would have been contagious on the trip home. Viruses commonly are transmitted before symptoms appear, Mina says, though that might not be the case with the Wuhan virus.

Aware of the new virus, the man told his health care provider right away that he might have been exposed, officials from Snohomish County say, so his caregivers had the right protection. He was placed in an isolation room at a local hospital in an abundance of caution, but he is not extremely ill, the officials said during a Tuesday telephone news conference. State and federal officials started Tuesday to track any people who may have been exposed to the man during his journey home or in the few days after his return.

The man told authorities he did not visit the open-air fish market in Wuhan, where the outbreak is believed to have begun, nor did he meet with anyone who was obviously sick -- raising concerns about how he might have caught the virus and whether those who spread the virus must have symptoms.

The U.S. government has begun screening passengers arriving from Wuhan at three American airports: Los Angeles (LAX), San Francisco (SFO) and New York’s JFK Airport. Soon, all travelers who have been in Wuhan will be required to go through one of five airports -- also including Chicago’s O'Hare International Airport (ORD) and Hartsfield-Jackson Atlanta International Airport (ATL) -- to make sure everyone returning from there has been screened.

Northwestern University infectious disease expert Robert Murphy, MD says that screening at five US airports isn't enough to keep the virus out of the country. "A Wuhan visitor or resident can easily get on a train, local plane or drive out of the city and then get on another flight from another city to the U.S. or anywhere," he said via email. "Anyone coming from China or admits to visiting China in the last month should be screened."

The man from Snohomish County would not have been caught by such a screen because he was not feverish when traveling. But the effort is still worthwhile because it will contain the number of people who may have been exposed to the virus and will educate all passengers on how to respond if they become ill within a few days, Marty Cetron, MD, director of the CDC’s Division of Global Migration and Quarantine, said during the Tuesday telephone news conference.

Are there any treatments?

There is no medication just for this virus, although Le Duc says experts in Galveston and other research facilities are working on possible treatments.

Patients, including the man in Washington, largely receive “supportive care,” which for a patient at home pretty much means fluids and a fever reducer like acetaminophen. In a hospital, supportive care can include many other measures, such as respiratory support for someone struggling to breathe, Mina says.

Mina says he’s heard that some patients in China are being treated with protease inhibitors, antivirals that were developed to treat people with HIV and that were used “somewhat successfully” to treat SARS.

The Washington man is hospitalized and isolated “because it’s the first person in the United States,” Chris Spitters, the health officer for the Snohomish Health District, said at the Tuesday news conference. “We will likely learn from this and future cases and adjust our recommendations accordingly.”

But the man is not very ill, Spitters said, and he “poses very little risk to staff or general public.”

How does a virus suddenly appear?

Although the virus was believed to have first infected people at a fish market, it is very unlikely that the disease is spread by fish, Lipkin says.

“This didn’t come from a fish. This came from a mammal,” and the same market probably sells other animals, he says. “The question is: What was in this market?” Middle East respiratory syndrome (MERS) is spread by camels, he says, and SARS was believed to have been passed on by civets, small nocturnal creatures that are like ferrets.

Wild animal markets are a huge way to pass new diseases to humans, says Lipkin, who has urged the closure of such markets for years, because both the 1999 H5N1 flu -- known as bird flu -- and the 2002-2003 SARS outbreak are believed to have started in one.

It’s not yet clear what animal is carrying the Wuhan virus, says Lipkin, who is an expert in identifying animal reservoirs for disease and says he has offered his services to the Chinese government.

And it’s possible, Mina says, that it didn’t come from a wild animal market at all. It’s not clear exactly when or where the outbreak began, with some genetic evidence suggesting it may have started as early as September.

A study suggesting that the disease may have jumped to people from snakes may be premature, Tedros said. “So far, there’s no conclusive evidence.”

Can our medical system prevent an epidemic?

Another question is: How ready is the American medical system to handle any outbreak of Wuhan coronavirus? Experts disagree.

Shira Doron, MD, an infectious disease specialist and hospital epidemiologist at Tufts Medical Center in Boston, says her hospital and many others are much better prepared for such an outbreak than they were in 2014, when a man traveled from West Africa to Dallas carrying the Ebola virus. He infected two nurses in Dallas before dying of his illness, striking fear in the public and among health care workers.

“Everybody’s come a long way since then. That’s for sure,” Doron says.

Her main concern is that since it is striking at the same time as flu season, many people, because of their travel history and symptoms, will come under suspicion even though they won’t have the coronavirus. “It may tax our resources for private rooms and equipment,” she says. “If this were happening in the summer, it would be easier to deal with.”

“The U.S. is totally unprepared for handling this epidemic," he said in a prepared statement. He compared the Wuhan virus to SARS. "Approximately 1,000 people died from SARS, and it would not surprise me if the same happens here," he said.

Still, for perspective, the flu kills 25,000 to 50,000 people per year, Mark Rupp, MD, an infectious disease specialist at the Nebraska Medical Center in Omaha, noted on a Facebook news conference Tuesday. “There’s a much higher level of risk from these more common viruses that we are used to encountering each and every year,” he said.

Could it end on its own?

SARS seems to have burned itself out with that one epidemic. MERS has bubbled along since 2012, sickening just under 2,500 people, mainly in Saudi Arabia and neighboring countries -- and killing one-third of them. But it has not reached the level of a pandemic. So does that mean there’s hope that the Wuhan coronavirus won’t become a pandemic?

Le Duc, from Galveston, says like the other viruses, you probably can’t catch this one very easily, so it might never become the global disaster some fear.

His team has been studying mice modified to have the human version of a receptor that allows a coronavirus to infect a person. With the genetic sequence in hand, and awaiting a version of the virus, potentially from the patient in Washington, he says his staff can help figure out how dangerous the Wuhan virus is likely to be and begin to come up with vaccines and treatments to address it.

“It’s weeks to get started, months to get a product ready for human testing,” says Le Duc, who is at the beginning of that process now.

But whatever we know now is likely to change, because we know so little about the Wuhan virus, says Nancy Messonnier, MD, director of the National Center for Immunization and Respiratory Diseases. “There is new information hour by hour, day by day that we are tracking and following closely,” she said on the Tuesday media call.

WebMD Health News Reviewed by Brunilda Nazario, MD on January 22, 2020

Sources

Nancy Messonnier, MD, director, National Center for Immunization and Respiratory Diseases.

Chris Spitters, MD, health officer, Snohomish Health District, Washington state.

Marty Cetron, MD, director, CDC’s Division of Global Migration and Quarantine.

Jim Le Duc, PhD, director, Galveston National Laboratory, University of Texas Medical Branch.

W. Ian Lipkin, MD, professor of epidemiology, Mailman School of Public Health, Columbia University.

Michael Mina, MD, PhD, epidemiologist, Harvard School of Public Health.

Shira Doron, MD, infectious disease specialist and hospital epidemiologist, Tufts Medical Center.

Mark Rupp, MD, infectious disease specialist, Nebraska Medical Center, Omaha.

CDC.gov.

AJC.com: “CDC to start screening for coronavirus at Hartsfield-Jackson.”

Robert Murphy, MD, infectious disease expert, Northwestern University

News conference, WHO.

New York Times: "Coronavirus Live Updates: China Bans Travel From More Cities."

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