A mysterious pneumonia had sickened at least 59 people in the Chinese city of Wuhan as of Sunday, and now Chinese researchers say a new coronavirus could be the cause.

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Details on the illness

Reports of the infection first broke in early December 2019. According to the World Health Organization (WHO), the main symptoms of the disease are fever and lesions in both lungs. Some patients have also reported breathing difficulties, according to WHO.

On Thursday, Chinese state media announced that the cause of the illness "is believed to be a new type of coronavirus," according to experts.

"Coronaviruses are a large family of viruses that range from the common cold to SARS," WHO said in a statement. "Some cause less-severe disease, some more severe. Some transmit easily from person to person, while others don't."

According to Chinese state media, the new coronavirus "is different from previous human coronaviruses that were previously discovered, and more scientific research is needed for further understanding."

As of now, the outbreak has been connected to a large live seafood market that sells exotic animals, too, leading experts to believe the disease has come through exposure to animals.

WHO said that the illness does not "transmit readily" between people. The Wuhan Municipal Health Authority has made statements saying there has been no person-to-person spread of the disease,

K.Y. Yuen, chair professor of infectious diseases at the University of Hong Kong's Faculty of Medicine, said the disease's link to a seafood market strongly suggests this is a unique microbe moving from animals to humans. Yuen added that, given advances in hospital isolation facilities, infection control, and laboratory diagnostic capabilities over the past 20 years, it's not likely this disease will lead to an epidemic.

However, some experts believe it's too soon to rule out human-to-human transmission.

Matthew Frieman, a coronavirus expert at the University of Maryland School of Medicine, said, "I don't know how you know that at all." He added that the number of people with the illness suggests that it's unlikely that animal-to-human contact is the only way the disease spreads.  

How officials are responding

Authorities in both Hong Kong and Singapore—where there are direct flights from Wuhan—have issued an alert and have quarantined any patients traveling from Wuhan who have signs of fever or breathing problems.

In addition, officials in Hong Kong have installed additional thermal imaging systems at its airport to detect and patients coming from Wuhan who have a fever. As of now, Hong Kong is isolating any cases until they can be tested.

In the United States, CDC sent out an alert to providers notifying them of the outbreak and urging them to ask any patients with severe respiratory infections whether they had recently traveled to Wuhan. CDC said no cases have been reported in the United States but that the agency is ready to respond "if additional public health actions are required."

Experts say it will be important for China to share information to help providers know what to look for when they come across a patient with pneumonia who recently traveled to Wuhan. China faced criticism after it initially covered up the emergence of SARS. The virus was detected in 2002, but officials only disclosed that information once it started spreading widely, according to the Wall Street Journal. Since then, China has revamped its disease control (Branswell, STAT News, 1/8; Khan, Wall Street Journal, 1/8; Wee/McNeil, New York Times, 1/8).