Your guide to coronavirus: Everything to know about Covid-19, the deadly virus alarming the world

Adrianna Rodriguez, George Petras, Ramon Padilla, Jim Sergent, Janet Loehrke, Grace Hauck and Ryan W. Miller, USA TODAY

The spread of China’s coronavirus, which has infected tens of thousands of people across dozens of countries, may have started with something simple – a person buying food for dinner at an outdoor market.

The potency and movement of the virus has rallied the international cooperation of various agencies and governments. On Jan. 30, the World Health Organization declared the coronavirus outbreak to be a "public health emergency of international concern," followed a day later by the United States' own declaration.

On Sunday, American passengers from the quarantined Diamond Princess cruise off the coast of Japan returned to the United States, including 14 Americans who tested positive for the virus.

At stake in the outbreak is not only the health of thousands of people but also significant parts of the world economy, including trade, manufacturing, travel and tourism.

Researchers say Chinese leaders are sharing their findings with the international scientific community, a contrast to the way they handled the 2003 outbreak of SARS. Last time, the government withheld information and received world criticism. 

President Donald Trump's top economic adviser, Larry Kudlow, said the White House is "disappointed" in what it sees as a lack of cooperation and transparency from Chinese officials as Beijing struggles to contain the burgeoning coronavirus.

Michael Ryan, executive director of the WHO health emergencies program, however, said that the group had no evidence to support the claim of lack of transparency by China and that he expects U.S. experts to be part of the WHO team in Wuhan, the epicenter of the virus.

At the same time, the outbreak has put a spotlight on censorship and free speech in China, where the death of a whistleblower doctor who was punished for trying to warn about the coronavirus has triggered a national backlash.

What is the Covid-19 virus?

The infection numbers are startling: Since Jan. 20, cases worldwide have surged to 71,902 across 29 countries, according to Johns Hopkins. The death toll stands at 1,775 as of Monday morning. All but five of the deaths have been in mainland China. There have been 15 cases in the U.S., and one U.S. citizen diagnosed with the coronavirus has died in Wuhan

A formal name for the coronavirus had been announced – Covid-19. WHO Director-General Tedros Adhanom Ghebreyesus said officials needed a name that did not refer to a geographical location, an animal, an individual or group of people. It also had to be pronounceable and related to the disease.

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How does coronavirus compare to SARS, MERS and the common flu?

Outbreaks like this have happened before, most notably with SARS in 2003 and MERS in 2015. While the new coronavirus has infected and killed more people than those outbreaks, its mortality rate is lower.

SARS, Severe Acute Respiratory Syndrome, is commonly used as a reference in coronavirus coverage, since both originated in China and share characteristics. In all, 8,098 SARS cases were recorded, with a death toll of 774. That’s a fatality rate of 9.6%.

MERS, Middle East Respiratory Syndrome, originated in Saudi Arabia and resulted in 2,499 cases and 861 deaths, giving it a higher fatality rate of 34.5%.

With current numbers, the fatality rate for Covid-19 is less than these other outbreaks, WHO estimated the mortality rate for the virus at about 2%.

The reported numbers are biased by cases that require medical treatment, and there are likely many more cases that are mild and not reported as they don't require treatment, said Lauren Gardner, a Johns Hopkins professor who has been mapping the outbreak.

However, confirmed coronavirus cases boomed this week as China altered its method for counting amid concerns over its handling of the crisis. China previously counted cases only when a person tested positive for the virus. Chest imaging and other medical diagnoses are now included.

Most coronavirus cases reported to date “have been milder, with about 20% of those infected experiencing severe illness,” the WHO said.

These numbers are still incomparable to this season's influenza impact. Based on its weekly influenza report, the Centers for Disease Control and Prevention estimates that there have been at least 26 million cases of flu, 250,000 hospitalizations and 14,000 deaths – including 92 children – in the U.S. this influenza season.

"Everybody is being cautious because we’re still learning about it, but right now you’re sitting in the midst of an influenza seasonal busy-ness," said Dr. David Hooper, chief of the Infection Control Unit at Massachusetts General Hospital.

"The risk is much higher for influenza for people in the U.S. than this new coronavirus."

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Is the virus just a problem for China? Are people quarantined?

The WHO classified Covid-19 as a global health emergency, reversing an early decision not to declare an emergency.

Mainland China has seen the greatest number of cases, with 70,554 confirmed cases as of Monday morning, according to Johns Hopkins.

As infection numbers rise, China has ordered some 60 million people in several cities in central Hubei province to stay where they are under strict lockdown measures. The government is doubling down, too, and ordered lockdowns expanded to include residential communities within urban and rural areas of the region.

The government also closed non-essential public places and banned public gatherings and the use of private vehicles.

Wuhan has been hardest hit. Airports and railway stations are closed and public transportation halted. Residents wear face masks to protect against infection. While a new, 1,000-bed coronavirus hospital was constructed in 10 days, there are shortages of medicine, protective masks and other supplies.

The virus is widespread across multiple countries beyond China, from Thailand to Australia to France. The first death outside China was recorded in the Philippines. Three other fatalities have been recorded in France, Hong Kong and Japan.

In the U.S., at least 15 people are known to be infected. Health officials early this month reported the first U.S. case of person-to-person spread of the virus – the husband of a Chicago woman who recently came down with the illness after visiting China. The couple was discharged from the hospital Friday.

A 60-year-old U.S. citizen diagnosed with the coronavirus died in Wuhan in what appears to be the first American fatality from the global virus outbreak, the U.S. embassy in Beijing reports.

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Meanwhile, the U.S. government has evacuated more than 800 Americans from central China to California on five chartered flights in recent weeks.

The first flight carried 195 American diplomats and some citizens at the end of January. They were all released and cleared to begin traveling to their homes earlier this week after U.S. health officials U.S. health officials issued a federal quarantine order for the first time in a half-century. 

Cruise ships are also quarantining thousands of passengers after several ships were impacted by the coronavirus. Diamond Princess, a Princess Cruises ship that was quarantined off the coast of Japan through Feb. 19, has had at least 285 cases of coronavirus diagnosed as of Saturday.

Nearly 400 American passengers were evacuated from the ship Sunday, including 14 who were allowed to fly back to the United States despite testing positive for the virus, the U.S. State Department and Health and Human Services said in a joint statement. They were not symptomatic. 

"The quarantine process failed," Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases at the National Institutes of Health, said Monday.

As two charter flights carrying the passengers landed at military bases in California and Texas overnight, the clock started on a new 14-day quarantine period to ensure those passengers don’t have coronavirus.

In Cambodia, passengers from Holland America's MS Westerdam finally disembarked Friday after the ship had been turned away from several ports, leaving the ship in limbo despite having no known coronavirus cases. The ship departed from Hong Kong on Feb. 1.

Subsequent flights have carried Americans to air force bases in California, Texas and Nebraska.

Other nations are also evacuating citizens and closely screening travelers returning home from abroad.

Delta, United and American canceled all of their China flights until late April in response to the coronavirus outbreak, becoming the first domestic carriers to make the move.

Hotels are following suit with Hilton closing about 150 of its hotels in China, translating to about 33,000 rooms. Wyndham Hotels & Resorts, has closed about 70% of its hotels in the country. Best Western Hotels & Resorts has 52 properties in China, and about 65% of them are closed.

Some hotels such as Marriott and Hyatt are waiving cancellation fees for guests staying in China or traveling elsewhere from China. 

Airbnb has also suspended bookings in Beijing with check-in dates from Feb. 7 to April 30. Bookings have also been suspended elsewhere in China: for Wuxi until Feb. 20; Yongchuan District (in Chongqing) until Feb. 29; and Wuhan until March 31.

Airbnb guests whose reservations get canceled will be refunded.

On Jan. 30, the U.S. State Department elevated its China travel advisory to level 4, recommending that Americans do not travel there.

When did the outbreak start? Where did coronavirus come from?

According to Chinese officials, Covid-19 first appeared Dec. 12 about 700 miles south of Beijing in Wuhan, a city with more people than New York and Chicago combined. Health officials say the outbreak originated at the Huanan Seafood Market.

Huanan Seafood, closed by officials on Jan. 1, was a wet market, one of a series of outdoor stalls selling fish and meat, some of it from wildlife. They are called wet markets because sellers slaughter and cut up animals and fish while customers wait.

The market is suspected because coronaviruses transmit zoonotic diseases, meaning they are transferred from infected animals to humans.

Researchers theorize that someone bought contaminated meat at the market, ate it, got sick and infected others, creating a ripple effect around the world. Bloomberg reported a 61-year-old man, a regular customer of the Huanan market, was the first to die from the virus.

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Not everyone believes the market theory. A Jan. 24 study by the British medical journal The Lancet suggests the outbreak started earlier than December and casts doubt on the market connection.

Pat Lord, teaching professor in the department of biology at Wake Forest University, said this particular outbreak probably came from a virus that originated in bats and another animal and then transformed to be able to infect humans. Health experts have confirmed human-to-human transmission in a number of countries.

The virus may have transferred to humans through pangolins, researchers at South China Agricultural University said last Friday.

The research team tested more than 1,000 samples from wild animals and a found a 99% match between the genome sequences of viruses found in pangolins – a scaly, heavily trafficked mammal – and those in human patients, the AFP reported, citing Chinese state media.

Similarly, SARS originated from a fruit bat that was transmitted to civet cats and then eaten as a delicacy in China, Lord said. 

"Bats seem to be a reservoir for quite a few viruses, like the rabies, Ebola or the Marburg virus," she said.

What are the symptoms of coronavirus?

Common signs of infection include fever, cough, shortness of breath and breathing difficulties. Experts are unsure of whether the virus is able to transmit before symptoms appear or after. If it worsens, it can cause pneumonia, severe acute respiratory syndrome, kidney failure or even death.

The virus can be spread from animals to people. But it also can be spread by coughing, sneezing and through close contact with an infected person or an object carrying the virus. Experts are still figuring out how long an infected person is contagious as they try to determine a point of transmission.

Coronaviruses are named after their appearance, round with a series of spikes made of proteins, resulting in a crown-like look. They're one of many viruses that cause colds and flu.

A new, evolved version, such as Covid-19, can cause more serious illnesses, some of which can be deadly to older people or those with weakened immune systems.

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Coronaviruses are found in a variety of animals. If passed from animal to human, the virus can change and infect other humans, who can spread the infection to others, according to the CDC.

Lord said that bats' evolution has made them become carriers of these diseases without actually getting sick. She thinks they pass around these viruses to each other because they live in such large colonies in relatively small quarters. 

Humans are partly to blame for outbreaks as development encroaches on bats' natural habitats, Lord said. Taking care of the environment to contain bats and keeping live markets clean are two ways humans can work to prevent outbreaks.

"The health of environment, the health of animals and the health of humans are all related," she said. "We have to think about the whole big picture, we have to protect everything." 

Is there a vaccine for the coronavirus?

There are no drugs or vaccines for coronaviruses yet, including Covid-19. Doctors can only treat the symptoms they cause.

However, scientists at The Peter Doherty Institute for Infection and Immunity in Melbourne, Australia, say they were able to successfully grow the coronavirus in cell culture outside of China for the first time ever.

Dr. Mike Catton, deputy director of the Doherty Institute, said in a statement the breakthrough provides crucial information “to assist in the assessment of effectiveness of trial vaccines.”

According to the South China Morning Post, China might already have a vaccine developed but needs more time to test it. Hong Kong University professor Yuen Kwok-yung told the paper it will take months to test the vaccine on animals and at least another year to conduct clinical trials on humans.

Scientists from Regeneron, a New York-based biotechnology giant, are using genetically altered mice to find rapid diagnostics, a vaccine and effective treatments. Engineered to mimic the human immune system, the mice are being exposed to pseudo coronavirus in hopes that they produce antibodies that block and treat the real infectious disease.

Who is most at risk of getting coronavirus?

Chinese scientists have decoded the Covid-19 DNA and made it public. Researchers are analyzing the data in hope of finding a vaccine.

Hooper said that experts are still learning about the virus and information remains limited.

However, he points to elderly and people who are sick with other conditions as a demographic who are over-represented in the coronavirus death toll.

"For those who do have the disease, it seems like the elderly and people with comorbid conditions are more likely to have serious illness," he said.

Hooper said it's unknown if women infected with the virus can have complications while pregnant, like the Zika virus, which causes microcephaly and other fetal brain defects.

How can you prevent catching the coronavirus?

As there's no available vaccine, the CDC recommends taking preventative measures to decrease the likelihood of infection

  • Wash hands often with soap and water for at least 20 seconds
  • Avoid touching the face with unwashed hands
  • Avoid close contact with people who are sick
  • Cough or sneeze into your elbow or use a tissue to cover it, and throw the tissue away
  • Clean and disinfect frequently touched objects and surfaces

How do doctors treat the coronavirus?

There’s no specific treatment for illnesses caused by human coronaviruses but the CDC recommends taking pain and fever medications, drinking plenty of liquids and staying home to rest.

SOURCE USA TODAY reporting; Johns Hopkins University; World Health Organization; Centers for Disease Control and Prevention; Food and Drug Administration; Associated Press; Reuters;

This article originally appeared on USA TODAY: Coronavirus symptoms, spread: How to protect from China virus Covid-19