China's Mystery Illness Continues to Spread Ahead of Lunar New Year, the World's Biggest Human Migration

Health officials in China have increased monitoring efforts for a mysterious form of pneumonia which has affected over 100 people, as the country gears up for the Lunar New Year—the world's biggest human migration.

China has reported 139 new cases of the illness caused by a new coronavirus, the World Health Organisation said Sunday. The WHO said the reports were "the result of increased searching and testing" for the virus among people sick with respiratory illnesses.

According to Reuters, China's National Health Commission said over the weekend that the bug appeared to be controllable. The organization will step up its efforts to track the infection as new year celebrations are due to start on January 24, with what is known as the Chunyun travel period set to last 40 days. According to Bloomberg, Chinese citizens will make up to three billion trips in what is the largest human migration on the planet. A spike in railway travel of 8 percent on last year is forecast.

Dr Suwannachai Wattanayingcharoenchai, head of Thailand's Department of Disease Control, said according to the Bangkok Post: "We are now on full alert to prevent a disease outbreak, especially during the coming Chinese New Year."

The WHO has not recommended any specific health measures for travelers. Individuals who have symptoms of a respiratory illness either during or after travel "are encouraged to seek medical attention and share their travel history with their health care provider," it said. The body advised travelers to keep up standard hygiene procedures to prevent the spread of a range of illnesses, including by washing hands and avoiding close contact with others, particularly "anyone showing symptoms of respiratory illness such as coughing and sneezing."

Coronavirus is the term used to describe a large family of viruses encompassing common colds as well as more serious illnesses such as Severe Acute Respiratory Syndrome (SARS). The virus has killed two people since it was first identified late last year in the city of Wuhan, about 700 miles south of Beijing with a population of more than 11 million people. One victim had serious underlying medical conditions, according to the U.S. Centers for Disease Control and Prevention (CDC).

The graphic below, provided by Statista, shows data on the new coronavirus outbreak in China, as well as information on past coronavirus outbreaks in Asia.

On Sunday, the WHO said new cases had been detected outside the city within China for the first time "over the past two days," in the capital Beijing and Shenzhen. This comes after it was confirmed in travelers from Wuhan in Thailand as well as Japan according to the CDC. The Yonhap news agency reported on Monday, citing the Korea Centers for Disease Control, that a Chinese woman who had traveled to Wuhan last week had fallen ill at South Korea's Incheon International Airport.

Last week, the CDC announced travelers entering the U.S. from Wuhan would be screened for symptoms of the condition. This is planned for the airports which receive the most travelers from Wuhan: San Francisco (SFO), New York (JFK), and Los Angeles (LAX).

According to the CDC, over 60,000 people fly from Wuhan to the U.S. each year, with around 10 percent of the total annual travel between the China and the U.S. happening in January due to the Lunar New Year.

The health body stressed the available evidence suggests the virus poses a "low" risk to the American public, but said "nevertheless, CDC is taking proactive preparedness precautions."

Animals seem to be the most likely primary source of the coronavirus outbreak, the WHO said, but there is "some limited human-to-human transmission occurring between close contacts." Most infected patients were exposed to a market where live animals are kept in Wuhan, the CDC said citing Chinese health officials. This suggests "this is a novel virus that has jumped the species barrier to infect people," the CDC said.

As more cases are identified and analyzed, the WHO said it hopes to "get a clearer picture of disease severity and transmission patterns.

"We will update and expand our guidance as we learn more," the body added.