Editor's note (2 Feb 2020): A previous version of the chart in this article incorrectly reported the case-fatality rate of H1N1. It is 0.02 percent. The city name of Marburg has also been misspelled; we regret the error.

Since December 31, the Wuhan coronavirus has killed at least 170 people and infected more than 8,000 across 20 countries, including the US.

The outbreak isn't currently considered a pandemic, however, despite its rapid spread. But the World Health Organisation has declared it a global public-health emergency, despite China putting Wuhan and other nearby cities under quarantine to stop the virus' spread.

Here's how the Wuhan outbreak compares to other major virus outbreaks in the last 50 years.

(Shayanne Gal/Business Insider)

The chart above does not include mosquito-borne viruses like Zika and Dengue fever.

All of these diseases jumped from animals to people

According to experts, the new coronavirus likely originated in bats. More than 75 percent of emerging diseases originate in animals; these are called zoonotic diseases, meaning they can jump from animals to people.

At least 10 outbreaks in the last century have spilled over to humans from animals such as bats, birds, and pigs.

Ebola jumped from fruit bats in west Africa 40 years ago and has killed more than 13,500 people in multiple outbreaks. The Marburg virus, SARS (severe acute respiratory syndrome), MERS (Middle Eastern respiratory syndrome), and Nipah also originated in bats.

The H7N9 and H5N9 bird flus, meanwhile, jumped from infected poultry to people in Chinese markets, together killing more than 1,000 people.

The 2009-2010 swine flu pandemic (also known as H1N1) started, of course, in pigs. It killed nearly 300,000 people in a global pandemic and spread to 214 countries in less than a year.

According to experts, diseases will continue to spill over from animals to humans as the global population grows. The more people there are on Earth, the more our species moves into wild habitats and encounters creatures that harbour viruses.

"Infectious diseases will continue to emerge and re-emerge. I think it's part of the world we live in now," Eric Toner, a senior scientist at the Johns Hopkins Centre for Health Security, previously told Business Insider.

"We're in an age of epidemics because of globalization, because of encroachment on wild environments."

This article was originally published by Business Insider.

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