University of Texas researchers say at least 128 cities in China had a 50% chance of getting a visit from someone with the new coronavirus prior to the Jan. 23 quarantine of the Wuhan region, where health officials say the outbreak originated. Based on the researchers’ travel models, pockets of the disease could still be undetected in China.

In a paper currently in press with the journal, Emerging Infectious Diseases, UT researchers, together with researchers from Hong Kong, mainland China and France, say the virus likely was able to reach a large portion of the country before authorities issued quarantine orders.

The team also estimated there were 11,213 cases of the coronavirus in Wuhan by the time of the quarantine — 10 times higher than official reports.

Early data in emerging epidemics can be limited, said Lauren Ancel Meyers, one of the lead authors of the study and a mathematical epidemiologist and professor of integrative biology. But using historic travel patterns, Meyers and a team of researchers were able to create a probable timeline of the virus’ progression.

The findings were produced by analyzing a huge amount of granular data, including nearly 60 million trips in and out of Wuhan prior to the quarantine. Using supercomputers in the Texas Advanced Computing Center, researchers were able to quickly analyze the probability of transmission in major Chinese cities. Several cities, which have reported no cases, had a 99% probability that an infected person visited, the study found. Those cities — each with a population of more than 2 million people — include Fushun, Laibin and Chuxiong.

"This risk assessment identified several cities throughout China likely to be harboring yet undetected cases of (Wuhan coronavirus) and suggests that early 2020 ground and rail travel seeded cases far beyond the Wuhan region quarantine," write the authors.

As of Feb. 4, more than 20,000 confirmed cases of the virus have been reported worldwide. Officials say 425 people have died as a result of the respiratory illness, all but two of whom were in mainland China. The new virus is a member of the coronavirus family that’s a close cousin to the SARS and MERS viruses that have caused outbreaks in the past.

Because symptoms sometimes don’t appear for up to two weeks, travelers could have carried the virus into cities without any knowledge. The study shows there is a 99% chance that at least one person carrying the virus traveled to Beijing, Guangzhou, Shenzhen and Shanghai by the time the Jan. 23 quarantine was put in place.

Meyers and Zhanwei Du, a UT computer scientist, worked with Chinese and French researchers and looked at road, train and air travel data, which they argue are more accurate than other models based solely on air travel.

"The quarantine will probably prevent future transmission out of Wuhan," Meyers said. "However, introductions of the novel coronavirus had already occurred throughout China and the world by the time the quarantine started."

Eleven cases of the virus have been reported in the United States. Although there have been a few scares in Texas, no cases have been confirmed in the state. Austin-Travis County Medical Director Mark Escott told members of the Austin City Council on Tuesday the risk of contracting the coronavirus in Texas currently is slim to none.

"That's reassuring because there's no risk of exposure unless there are cases," Escott said. "It's important for us to remember and share with the community because there certainly is a risk of xenophobia associated with people who are Asian Americans or Chinese Americans, and that is not necessary and inappropriate."

Escott said people should remember that if they come across someone coughing who looks like they might have the flu, there’s about a 35% chance they have the flu and virtually a 0% chance they have the coronavirus right now.