Dr. Anthony Fauci, who plans to retire at the end of the year, told MSNBC's Rachel Maddow Monday night that we are seeing an increased threat from new and insurgent viruses, such as monkeypox, polio, SARS, Zika and others.

"There are probably a number of complex reasons why that's the case," he said.

"If you look at the outbreaks that you just enumerated a moment ago, it really follows a pattern that we've known for some time, that about 70 percent to 75 percent of all the new emerging infectious diseases are zoonotic. Namely, they jump from an animal species to a human.

"We saw that with HIV. We saw that with ebola. We see that with monkeypox. And we're seeing with this historic pandemic of COVID-19, which almost certainly evolved the way SARS-COV-1 did from an animal reservoir such as a bat in the environment that jumped species.

So if we really want to pay attention to how we can mitigate this, we have to pay much more attention to the animal/human interface and to what we are doing intentionally or inadvertently of perturbing that animal/human interface by encroaching upon rain forests, by getting involved in interfacing with animals such as in the wet markets, which occur in China, when you bring in animals where you don't have any idea what disease they're harboring and you put them in close touch with humans.