Edgar Walters, Texas Tribune

A man who may have had contact with 100 other people is in isolation at a Dallas hospital after being diagnosed with Ebola, a deadly virus that has killed more than 3,000 people in West Africa.

Before a packed crowd in the White House’s state dining room, President Obama on Friday nominated San Antonio Mayor Julián Castro to become the newest — and youngest — member of his cabinet, as the secretary of housing and urban development.

“I am nominating another all-star who’s done a fantastic job in San Antonio over the last five years,” the president said between jokes about the “good-looking” mayor who had proved to be a “pretty good speaker.”

Pending Senate confirmation, Castro will replace Shaun Donovan, whom the president has tapped as the new director for the Office of Management and Budget.KUT's Ben Philpott explains the politics behind Castro's move to Washington.