(Reuters) - China locked down the central city of Wuhan a year ago at the start of the Lunar New Year, the country's biggest holiday, as it battled to contain the spread of a novel coronavirus.
Following is a timeline of key events since the first cases of the virus were detected in the city of 11 million residents in Hubei province.
Dec. 31, 2019: China alerts the World Health Organization (WHO) of 27 cases of "viral pneumonia" in Wuhan. Authorities shut down a wet market in the city the next day, after discovering some patients were vendors or dealers.
Jan. 11, 2020: China reports 61-year-old man dies of the viral illness. Preliminary lab tests cited by Chinese state media point to a new type of coronavirus.
Jan. 20: China confirms person-to-person spread after medical staff are infected.
Jan. 23: China locks down millions of people in Wuhan city and Hubei province as the death toll rises to 18.
Jan. 24-25: More medical professionals are sent to Wuhan to help treat patients as fatalities rise to 56.
Jan. 25: China bans wildlife trade after the virus was traced to a Wuhan animal market. The Lunar New Year holiday is extended for workers and schools.
Feb. 4: The city's first makeshift hospital, Huoshenshan - built from scratch in just eight days - starts to receive patients.
Feb. 7: Chinese ophthalmologist Li Wenliang, who had been reprimanded for issuing an early warning about the Wuhan outbreak, dies, triggering wide public mourning and rare expressions of anger against the government.
Feb. 16: 25-member China-WHO team begins nine-day field tripin China.
Feb. 22: Team arrives in Wuhan and learn about epidemic control measures and medical treatments.
March 10: Chinese President Xi Jinping makes first visit to Wuhan since the outbreak. Wuhan shuts last of 14 makeshift hospitals.
March 18: Wuhan registers zero new confirmed COVID-19 cases and authorities begin to gradually withdraw medical workers from Hubei province.
April 8: Wuhan begins allowing people to leave the city for the first time since the crisis, officially ending the lockdown.
May 13: Authorities in Wuhan launch campaign to test all of its residents after a cluster of new cases raises fears of a second wave of infections.
Dec. 18: WHO says it will send a team of 10 scientists toWuhan next month.
Jan. 14, 2021: The WHO team arrives in Wuhan, as China ramps up efforts to contain a resurgence of COVID-19 infections in its northeast.
(Compiled by Jacqueline Wong; Editing by Kim Coghill)