Officials in a Maryland county say they “will spare no time or expense” investigating the circumstances surrounding the coronavirus death of a veteran public health worker. Chantee Mack’s relatives and coworkers believe she contracted the virus on the job. The probe follows a story by Kaiser Health News and The Associated Press two weeks ago focusing on the 44-year-old disease intervention specialist at the Prince George’s County Health Department. Union officials say Mack was among at least 20 employees infected by the coronavirus. The outbreak underscores the stark dangers facing the nation’s front-line public health army.