Just hours after D.C. Mayor Muriel E. Bowser confirmed 1,000 covid-19 deaths in her city, she made another somber announcement, this one far more personal: Her sister had died of the virus.

Mercia Bowser, who died Wednesday morning at age 64, was the eldest of the six Bowser siblings, raised in a family deeply involved in the District and its politics. The mayor, 48, is the youngest.

“Mercia was loved immensely and will be missed greatly, as she joins the legion of angels who have gone home too soon due to the pandemic,” Bowser (D) wrote in a statement Wednesday afternoon. “I ask that you continue to keep those who have been lost or impacted by the pandemic and those who are working so hard to protect us from it in your thoughts and prayers.”

She thanked the staff at Washington Hospital Center who treated Mercia for coronavirus-related pneumonia, and said that her sister was retired from a career serving children, the elderly and people with behavioral disorders through Catholic Charities and the D.C. Office on Aging.

Mercia’s work included advising Metro on services for people with disabilities and helping train D.C. police cadets on crisis intervention, as well as providing services for people with mental illnesses and mental and physical disabilities, according to professional websites.

The mayor’s statement listed many siblings, nieces, nephews and friends who mourn her sister, along with their parents, Joseph and Joan Bowser.

Mercia Bowser was a graduate of Fisk University, a historically Black private university in Nashville. Although she and her siblings were raised Catholic, she was active at Israel Metropolitan Christian Methodist Episcopal Church in the Petworth neighborhood, Bowser’s statement said.

She was in high school when Muriel — the only other girl in the family — was born.

When Bowser first ran for mayor in 2014, a profile of her in The Washington Post recounted how Mercia gently teased her for following in the politically active footsteps of their father from the time she was a child.

Mercia called Muriel “JB Jr.”

As mayor, Bowser has been the public face of the District’s coronavirus response — making choices about what to close and what to open in the city, including schools and restaurants. Twice a week at news briefings, she shares the latest numbers and reminds residents to wear masks and maintain social distance.

Almost every time, within the first minutes of her remarks, she uses the word “tragically” before addressing the virus death toll.

On Wednesday morning, Bowser declared “A Day of Remembrance for Lives Lost to COVID-19” and encouraged houses of worship to honor the city’s 1,000 dead at 6 p.m.

The mayor, who is a generally private person and rarely mentions her daughter, parents or siblings, called the thousandth death “a reminder that this pandemic has forever changed families and communities.”

“Even when the pandemic ends, for many, the pain and loss will still be there,” she said.

Rebecca Tan contributed to this report.