David Quammen is the author of Spillover and Breathless, and has spent decades writing about evolution, emerging disease, and places where human beings meet the natural world.

Part of what resilience looks like is strong county public health departments with good people in the top job who are able to take some political heat, people who are capable of keeping a couple of things in their mind at one time.

What does it look like for an 11-year-old kid not to be able to go to school but have to spend an entire year learning online? What's the cost to the cancer patients in our community if our hospital becomes a no-go zone? What's the cost to the people with asthma and diabetes? Thinking about all those things is part of resilience as I understand it.

Prevention begins much further upstream.

But I think we have three huge problems, human-caused problems on this planet.

And they run parallel to one another, like three big brown overflowing rivers.

And those three problems are climate change, loss of biological diversity, and the threat of pandemic disease.

And they all have the same source, these big brown rivers.

And what can we say about this guy? I mean, is he, what do we know about him?

If we had to guess, if we had to guess, that human was probably a Bantu man living very near the forest or in the forest in southeastern Cameroon.

He was hunting.

Maybe he had a bow and arrow, maybe he had a spear, and, uh, [whooshing] [chimpanzee shrieking] he kills a chimpanzee.

Bingo, here's a big pile of meat, and he starts to butcher it.

He's cutting open the chest cavity, he's pulling out organs, and [blade slicing] he cuts himself, and he gets blood-to-blood contact, chimpanzee blood against his blood.

What happens is that the virus in the chimpanzee blood found itself in an environment that was unexpected, that was alien to it, but was not too much different from the biochemical environment it had been in, chimpanzee blood.

And into the city.

Why?

Yeah.

Okay.

Let's start with Tom Lovejoy.

Tom Lovejoy was a great man.

He died about, uh, two, two and a half years ago.

Um, um, and he became a, a, an important...

[chuckles]

Here's David Quammen again, who became close friends with Mary in Philadelphia.

When I say she was something of a flibber in the 1920s, I'm telling you the truth.

I got to know her so well that she told me everything about herself, sometimes embarrassing things.

[laughs] She lived to be 99 and a half, and I remember at one point she threw her arm back like this and she said, "I know what old age is for, David." And I said, "What?" She said, "Repentance." Okay? Repentance.

So she's very different from Jim in that way.

First, there were the late night phone calls.

Anyway, the, uh, local newspapers got ahold of it, and girls started calling the house and saying, "Is James there? Is James there?" And Mary would say, "Yes, but this is Pussy Galore and he's busy."