The World Health Organization (WHO) on Tuesday said there is evidence of human-to-human transmission of a new coronavirus in China, leading health officials to warn hospitals worldwide that virus could lead to a wider outbreak.

Background

Reports of the infection in people in China's Wuhan province first broke in early December 2019. According to the WHO, the main symptoms of the disease are fever and lesions in both lungs. Some patients have also reported difficulty breathing, according to WHO.

Last week, 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."

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 warns of possible outbreak

On Monday, Thai authorities announced that a 61-year-old woman from Wuhan has been quarantined in Thailand with the virus, marking the first case of the virus being detected outside of China, STAT News reports.

Thai Health Minister Anutin Charnvirakul emphasized that the woman "was infected with the virus from outside Thailand."

In a statement, WHO said, "The possibility of cases being identified in other countries was not unexpected, and reinforces why WHO calls for on-going active monitoring and preparedness in other countries."

On Wednesday, Chinese officials said scientists cannot rule out the possibility of human-to-human transmission. Preliminary investigations indicate that most patients who've contracted the virus had contact with the market, though a woman may have contracted the virus from her husband, who worked at the market, the Wuhan Municipal Health Commission said in a public notice. The woman might have contracted the virus from food her husband brought home, but because it took several days for her to show symptoms, it's possible that she got the virus from her husband, the Associated Press reports.

Earlier this week, According to Maria Van Kerkhove, acting head of WHO's emerging diseases unit, said, based on the information available, there is a possibility "that there is limited human-to-human transmission, potentially among families, but it is very clear right now that we have no sustained human-to-human transmission." Van Kerkhove added, "It is still early days, we don't have a clear clinical picture."

Still, WHO said it is preparing for the possibility of a wider outbreak.

At this point, there is no specific treatment for the virus. However, Van Kerkhove said that anti-virals are being considered and could be "re-purposed" (Nebehay, Reuters, 1/14; Joseph, STAT News, 1/13; Larson, AFP/Science Alert, 1/13; AP/CBS News, 1/15).