'Start Here': Kirstjen Nielsen quits Homeland Security, and a kidnapped American tourist is freed

Here's what you need to know to start your day.

It's Monday, April 8, 2019. Let's start here.

1. Homeland insecurity

Department of Homeland Security Secretary Kirstjen Nielsen stood next to President Donald Trump at the U.S.-Mexico border on Friday.

Two days later, she walked into the White House and quit.

Trump confirmed her resignation on Twitter after a meeting about border security turned into a discussion over her future, sources told ABC News.

However sudden the news felt, it was a long time coming, ABC News White House Correspondent Tara Palmeri tells us on "Start Here."

"It was always known that President Trump was not happy with Nielsen," Palmeri says. "It was a matter of not if it will happen, but when it will happen."

2. Tourist trap?

An American tourist and her Congolese tour guide are safe and in "good health" after they were kidnapped in Uganda and a $500,000 ransom was demanded, police said.

A spokesperson for Wild Frontiers Uganda told ABC News a ransom was paid -- it's unclear exactly how much or by whom -- raising concern over whether doing so may encourage more kidnappings, Senior Foreign Correspondent Ian Pannell reports from Queen Elizabeth National Park.

"They want tourists to come back, they want them to see that this is a safe place, that it's an unprecedented event," Pannell says on today's podcast. "If money's changing hands in exchange for foreign tourists, then that potentially endangers others."

3. Fungus among us

A deadly, drug-resistant fungus has broken out in healthcare facilities -- and it's spreading.

The Centers for Disease Control and Prevention described Candida auris as a "serious global health threat" that can cause bloodstream infections and is difficult to identify with standard technology. More than 587 cases have been confirmed in the U.S., mostly in New York City, New Jersey and Chicago, according to the CDC.

"What we've learned is, this microbe, Candida auris, is resistant to the typical cleaning agents that hospital and health care facilities often use," says infectious disease specialist Dr. Todd Ellerin. "If we don't change the way we clean rooms, then the Candida will hang out there. It could potentially infect the next person that enters the room."

4. Tangled with weed

Some immigrants fear careers in the legal cannabis industry have hurt their chances for full citizenship.

"I was led down a path to confess in my [citizenship] interview that I broke the law, that I willingly had known that I had broken the law," Oswaldo Barrientos, who worked at a marijuana dispensary in Colorado, tells ABC News.

Because marijuana remains illegal under federal law, a related job may disqualify someone from lawful residency, ABC News' Clayton Sandell explains on "Start Here."

"It's legal on one level," he says, "and illegal on another."

"Start Here," ABC News' flagship podcast, offers a straightforward look at the day's top stories in 20 minutes. Listen for free every weekday on Apple Podcasts, Google Podcasts, iHeartRadio, Spotify, Stitcher, TuneIn or the ABC News app. Follow @StartHereABC on Twitter, Facebook and Instagram for exclusive content and show updates.

Elsewhere:

'Leaving only a human skull and a pair of pants': Lions feast on a suspected poacher killed by an elephant.

'John asked co-workers to take pictures of him': A man accused of murdering his elderly mother asks colleagues to help with his alibi.

'We are pleased to be able to reach resolution in this matter': Motel 6 agrees to pay $12 million after illegally sharing the personal information of 80,000 customers with U.S. immigration officials.

From our friends at FiveThirtyEight:

Willians Astudillo is a baseball enigma: While he looks something like Bartolo Colon, he's hitting like Ty Cobb.

Doff your cap:

The U.S. Postal Service said it will honor George H.W. Bush by releasing a commemorative stamp on June 12, which would've been the former president's 95th birthday.

The stamp features a portrait of Bush painted by Michael J. Deas from a 1997 photograph taken by Timothy Greenfield-Sanders.

Bush, the 41st president, died Nov. 30, 2018.