Latest coronavirus developments in the U.S.

First case in DC.: Washington DC Mayor Muriel Bowser said the district's first confirmed case of coronavirus is a male in his 50s, and a DC resident; the source of his contamination remains unclear.

"He has no history of international travel and no contacts with a confirmed case," Bowser told reporters, adding the man is now being treated in a local hospital and there's no need to declare a state of emergency.

Speaking at a briefing Saturday night, the mayor also said the DC government is also aware of another unnamed person who recently visited DC and was diagnosed with the virus at a Maryland hospital

Marine tested positive: The Pentagon on Saturday said a U.S. Marine in the DC area has tested positive for the virus. The serviceman recently returned from official travel overseas.

It would be the third case among the U.S. military. The other two are sailors in Italy and South Korea.

CPAC attendee tests positive: One attendee at last week's Conservative Political Action Conference (CPAC) in National Harbor, Maryland contracted the coronavirus. 

Organizers said the person had "no interaction" with U.S. President Donald Trump or Vice President Mike Pence, who also attended the event.

Total cases over 440: According to local media tally, there're at least 445 confirmed or presumptive positive cases across 30 states in the U.S. Death toll now stands at 19.