China’s coronavirus, like many of its fast-growing pathogens, started out by entering the ecosystem innocently enough, in mice and rats. Over the course of a decade or so, its proliferation into more exotic hosts revealed the origin of a global problem — and the need for inventors to think about future transportation systems.

To deal with infectious disease, a more global method of transportation is required, said Avinash Sarkar, of Malvern, Penn., an MIT bioengineer.

In October 2015, a stray cat infected an infected man in Yulin, a city in southwestern China. The virus, then called Middle East Respiratory Syndrome Coronavirus, or MERS-CoV, has since spread into Asia, Europe and the Americas.

Nearly two years later, the virus is believed to have originated in the Middle East, possibly migrating to mice or rats through a food import route.

The virus is often described as a mild infection, but serious symptoms can develop into septicemia and septic shock, which can also be fatal.

Chi-Chi Ling / Associated Press People wearing protective glasses inside the quarantine area at the Hong Kong International Airport Nov. 18, 2010, while boarding an S. Korean Airways flight to Beijing. Children at Hong Kong's mainstream schools are monitoring their activity as well as that of their peers in mainland China where the country's worst outbreak of a deadly virus has infected a total of 47 children and six adults. Chi-Chi Ling / Associated Press People wearing protective glasses inside the quarantine area at the Hong Kong International Airport Nov. 18, 2010, while boarding an S. Korean Airways flight to Beijing. Children at Hong Kong's mainstream schools are monitoring their activity as well as that of their peers in mainland China where the country's worst outbreak of a deadly virus has infected a total of 47 children and six adults. (Chi-Chi Ling / Associated Press)

In 1999, a strain of H5N1 flu was found in mice from Bangladesh to Georgia. They were carrying a newly identified, devastating strain of bird flu.

Tens of millions of people died worldwide, driven to extreme suicide. More than 100,000 were hospitalized. The global travel industry took a hit.

The virus led to scientific discoveries that helped the control of the 1918 pandemic, making it easier to make vaccines and treatments. The move toward disinfecting surfaces didn’t happen until after it was discovered.

In 2012, the same virus that spread to Thailand mutated and caused a new strain of the Hong Kong bird flu. The virus, now called H5N1, has infected nearly 750 people, has caused 179 deaths.

A 2014 virus infected chickens in China and spread to Europe and Asia. A 2015 virus infected people in Vietnam.

It can be hard to separate fact from fiction. Here are some of the ideas from around the world about potential ways the coronavirus could spread.

The Islamic State: When terrorists in Syria and Iraq broke free of containment in 2014, many feared the virus — a simultaneous flight of a single strain of bird flu from birds and humans — could spread to Europe.

David Bailey / EPA Anti-virals from Denmark and Russia caught in the Arab peninsula start to flourish along the coast of Egypt, seeking new customers as the days draw on. Anti-virals from Denmark and Russia caught in the Arab peninsula start to flourish along the coast of Egypt, seeking new customers as the days draw on. (David Bailey / EPA)

The terrorist threats: Islamic State fighters grew mistrustful of vaccination campaigns in Eastern Europe, causing some disease-free believers to find chigger treatments to kick the itch.

Yemen: The virus was once thought of as merely transmitted from goats to sheep. But late in 2015, the virus moved from the Middle East to Yemen and spread to a number of countries.

Three of the main drugmakers worked on antiviral treatments — using genetic material taken from the virus — but it took several months to develop the drugs. The virus is still evolving, the company officials said, and vaccinations are needed to keep some pandemic threats in check.

Australia: Right next door to Hong Kong, some Australians were infected by the coronavirus. Between December 2014 and May 2015, the virus carried hundreds of viruses across Australia.

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