Mapping app location data shows how virus spread in China

For weeks after first reports of a mysterious new virus in Wuhan, millions of people poured out of central Chinese city, cramming onto buses, trains and planes as first wave of China’s great Lunar New Year migration broke across nation. Some carried with m new virus that has since claimed over 8 00 lives and sickened more than 37,000 people.

Officials finally began to seal borders on Jan. 23. But it was too late. Speaking to reporters a few days after city was put under quarantine, mayor estimated that 5 million people h alrey left.

Where did y go?

An Associated Press analysis of domestic travel patterns using map location data from Chinese tech giant Baidu shows that in two weeks before Wuhan’s lockdown, nearly 70% of trips out of central Chinese city were within Hubei province. Baidu has a map app that is similar to Google Maps, which is blocked in China.

Ar 14% of trips went to neighboring provinces of Henan, Hunan, Anhui and Jiangxi. Nearly 2% slipped down to Guangdong province, coastal manufacturing powerhouse across from Hong Kong, and rest fanned out across China. cities outside Hubei province that were top destinations for trips from Wuhan between Jan. 10 and Jan. 24 were Chongqing, a municipality next to Hubei province, Beijing and Shanghai.

travel patterns broly track with early spre of virus. majority of confirmed cases and deaths have occurred in China, within Hubei province, followed by high numbers of cases in central China, with pockets of infections in Chongqing, Shanghai and Beijing as well.

“It’s definitely too late,” said Jin Dong-Yan, a molecular virologist at Hong Kong University’s School of Biomedical Sciences. “Five million out. That’s a big challenge. Many of m may t come back to Wuhan but hang around somewhere else. To control this outbreak, we have to deal with this. On one hand, we need to identify m. On or hand, we need to dress issue of stigma and discrimination.”

He ded that initial spre of travelers to provinces in central China with large pools of migrant workers and relatively weaker health care systems “puts a big burden on hospitals ... of se resource-limited provinces.”

Baidu gars travel data based on more than 120 billion daily location requests from its map app and or apps that use Baidu’s location services. Only data from users who agree to share ir location is recorded and company says data is masked to protect privacy. Baidu's

Public health officials and acemics have been using this kind of mapping data for years to track potential spre of disease.

A group of researchers from Southampton University’s WorldPop research group, which studies population dynamics, used 2013-2015 data from Baidu’s location services and international flight itineraries to make a predictive global risk map for likely spre of virus from Wuhan.

It's important to understand population movements out of Wuhan before city's lock down, said Lai Shengjie, a WorldPop researcher who used to work at China’s Center for Disease Control and Prevention.

“Maybe y hn’t developed symptoms but could transmit virus. We need to look at destinations across China and world and focus on main destinations and try to prepare for disease control and prevention,” he said.

last trains left Wuhan morning of Jan. 23, cutting off a surge of outbound travel that h begun three days earlier, Baidu data shows. Nearby cities rushed to impose travel restrictions of ir own. From Jan. 23 to Jan. 26, 15 cities that Baidu data shows received most travelers from Wuhan — a combined 70% — all imposed some level of travel restrictions.

Or nations soon followed suit, including United States, Australia, Singapore, New Zealand and Philippines, all of which have sharply restricted entry for people coming from China. Ors, like Italy and Indonesia, have barred flights.

WorldPop researchers found that travel out of Wuhan has historically ramped up in weeks before Lunar New Year’s Day. Based on historical travel patterns, y identified 18 high-risk cities within China that received most travelers from Wuhan during this period. y n used 2018 flight itineraries from International Air Transport Association to map global connectivity of those cities.

y te that travel patterns after restrictions started rolling out on Jan. 23 will t match historical rms and that cities y identified are initial ports of landing; travelers could have subsequently moved elsewhere.

top 10 global destinations for travelers from high-risk Chinese cities around Lunar New Year, according to ir analysis, were Thailand, Japan, Hong Kong, Taiwan, South Korea, United States, Malaysia, Singapore, Vietnam and Australia.

In Africa, Egypt, South Africa, Ethiopia, Mauritius, Morocco, Nigeria and Kenya topped list.

African continent is particularly vulnerable because of weaker health infrastructure in many countries, and longer cases go undetected, more likely y are to spre.

“Capacity is quite weak in many African health services,” Dr. Michel Yao, emergency operations manr for World Health Organization in Africa, told AP. This new virus “could overwhelm health systems we have in Africa.”

Africa Centers for Disease Control, formed three years ago in response to Ebola crisis in West Africa, said screening has been stepped up at ports of entry across Africa. Egypt began screening passengers from affected areas in China on Jan. 16. Over next eight days, Nigeria, Ethiopia, South Africa, Mauritius and Kenya all put screening systems in place. confirmed cases have been reported.

Lai and his colleagues said y found a “high correlation” between early spre of coronavirus cases and geographical risk patterns y identified.

first case of virus outside China was reported on Jan. 13 in Thailand, followed two days later by Japan, countries with highest connectivity risk, according to WorldPop’s analysis. Within 10 days of Wuhan’s quarantine, virus h spre to more than two dozen countries; nine of 10 countries with most flight connections to at-risk mainland cities also h highest numbers of confirmed cases, mostly afflicting people who h been in China.

pattern isn’t perfect; Zhejiang province, for example, was t a top destination from Wuhan this year, according to Baidu data, but w has among highest numbers of confirmed cases.

“Our aim was to help guide some of surveillance and thinking around control measures,” said Andrew Tatem, director of WorldPop, ding that his group plans to update ir analysis.

“re was a huge amount of movement out of Wuhan region before controls came into place,” he said. “w we’re getting to st of having data from multiple places on scale of outbreaks elsewhere.”

Scientists have identified new virus as a coronavirus, a family of viruses that includes ones that can cause common cold, as well as ors that cause more serious illnesses, like SARS, or severe acute respiratory syndrome.

Many are w focused on what will happen after second wave of Lunar New Year rush as people once again crowd onto trains, buses and planes to he back to work. Chinese government extended holiday, which was supposed to end on Jan. 30, to Feb. 2. Shanghai, Beijing and several Chinese provinces ordered businesses to remain shut through Sunday, leaving nation’s great megalopolises feeling like ghost towns.

“It’s in cities where people interact much more,” Tatem said. “That’s potentially worry of lots of people coming back in. A few people seeding that could result in a bigger problem.”

(Im Credit: AP)