The novel coronavirus outbreak, which began in Wuhan, China, in December, has expanded to touch nearly every corner of the globe. At least 98,000 people around the world have been sickened and thousands have died.
The World Health Organization has declared the virus a global health emergency and rated COVID-19's global risk of spread and impact as "very high," the most serious designation the organization gives.
Here's a timeline of how the outbreak has unfolded so far:
Dec. 31, 2019: WHO learns mysterious pneumonia sickening dozens in China
Health authorities in China confirm that dozens of people in Wuhan, China, were being treated for pneumonia from an unknown source. Many of those sickened had visited a live animal market in Wuhan and authorities said there wasn't evidence of the virus was spreading from person to person.
Jan. 11, 2020: China reports 1st novel coronavirus death
Chinese state media reports the first death from novel coronavirus, a 61-year-old man who had visited the live animal market in Wuhan.
Jan. 21, 2020: 1st confirmed case in the United States
A man in his 30s from Washington state, who traveled to Wuhan, is diagnosed with novel coronavirus. Japan, South Korea and Thailand also report their first cases a day prior.
Jan. 23, 2020: China imposes strict lock-down in Wuhan
China imposes aggressive containment measures in Wuhan, the epicenter of the outbreak, suspending flights and trains and shutting down subways, buses and ferries in an attempt to stem the spread of the virus.
Jan. 30, 2020: WHO declares global health emergency
For the sixth time in history, the World Health Organization declares a "public health emergency of international concern," a designation reserved for extraordinary events that threaten to spread internationally.
Feb. 5, 2020: Diamond Princess cruise ship quarantined
More than 3,600 passengers are quarantined on a cruise ship off the coast of Yokohama, Japan, while passengers and crew undergo health screenings. The number of confirmed cases on board the ship would eventually swell to more than 700, making it one of the largest outbreaks outside of China.
Feb. 11, 2020: Novel coronavirus renamed COVID-19
The World Health Organization announces that novel coronavirus' formal new name is COVID-19. "Co" stands for coronavirus, "Vi" is for virus and "D" is for disease. Health officials purposely avoid naming COVID-19 after a geographical location, animal or group of people, so as not to stigmatize people or places.
Feb. 26, 2020: 1st case of suspected local transmission in the United States
The Centers for Disease Control and Prevention confirm the first case of COVID-19 in a patient in California with no travel history to an outbreak area, nor contact with anyone diagnosed with the virus. It's suspected to be the first instance of local transmission in the United States. Oregon, Washington and New York soon report their own cases of possible community transmission.
Feb. 29, 2020: 1st death reported in the United States
The first COVID-19 death is reported in Washington state, after a man with no travel history to China dies on Feb. 28 at Evergreen Health Medical Center in Kirkland, Washington. Two deaths that occurred Feb. 26 at a nearby nursing home would later be recorded as the first COVID-19 deaths to occur in the United States.
March 3, 2020: CDC lifts restrictions for virus testing
The CDC issues new guidance that allows anyone to be tested for the virus without restriction. Previously, only those who had traveled to an outbreak area, who had close contact with people diagnosed with COVID-19 or those with severe symptoms, could get tested.
Timeline: How coronavirus got started