As a mysterious new virus enveloped central China’s Wuhan early this year, Liu Zhiming mobilized all the resources of his hospital in the city’s Wuchang district to deal with the thousands of sick people arriving daily, threatening to overwhelm the local health care system.

That dedication appears to have cost him his life, with Wuhan’s health bureau announcing Tuesday that he became infected and died despite “all-out” attempts to save him.

Liu is at least the seventh health worker to die of the COVID-19 disease among the more than 1,700 doctors and nurses who have become sick. His death comes as authorities are cautiously cheering a reduction in the number of new daily cases and deaths, along with the results of a study showing most people who contracted the virus experienced only mild symptoms.