More than half a millennium ago, the bubonic plague wiped out half the population of Europe. But it has not disappeared from the Earth: an epidemic appeared suddenly earlier this year in Madagascar.
And this without any effort at weaponizing such a deadly threat.
Now, Kim Jong Un is said to be adding biological weapons to his arsenal of death and destruction, threatening to spread a pandemic far beyond the borders of any country he might be targeting. The White House's new national security strategy says North Korea "is pursuing" biological weapons, a claim Kim Jong Un's regime denies.
Is the United States or the world prepared? Not remotely.
It's still not known which specific diseases he might be trying to weaponize, but the World Health Organization has identified five horrific ones that could be used by any nation or terrorist organization anxious to spread havoc and panic on a global scale: anthrax, botulism, plague, smallpox and tularemia.
WHO has also identified 14 other diseases that have caused epidemics or pandemics in recent years.
It has recently identified a new strain of meningitis that has already begun spreading across Africa, causing at least 2,500 deaths, with a possible contagion to some 34 million people.
Since this summer, the Trump administration has been developing its National Biodefense Strategy, due sometime next year -- a follow-on to the President's "America First" National Security Strategy.
But bioweapons respect no borders, are hardly precisely targetable, especially in their vast threat to all humanity, yet require total and absolute global cooperation to resist or defend.
These are concepts that appear all but anathema to a Trump administration obsessed with America first.
Since biological threats are potentially easier to mount and more difficult to monitor than the delivery of nuclear weapons to their targets, the United States appears already to be far behind any possible response to such a potential threat.
The country is certainly getting better at controlling, isolating or even developing vaccines against some pathogens.
But in each case, the spread was quickly circumscribed, its origins easily determined, the patients isolated. Such action is hardly possible for many biological weapons, whose spread can be quick, widespread and all but undetected until a pandemic stage is suddenly upon us.
"We need a public health emergency fund, similar to the fund that we have" with the Federal Emergency Management Agency for natural disasters, says Dr. Anthony Fauci, who's dealt with epidemics from Ebola to Zika as director of the National Institute of Allergy and Infectious Diseases.
But such a fund is still a minimum response. Indeed, we need far more than that.
What we really need is a governmentwide, integrated capacity to deal with bioweapon attacks.
The funding for the tip-of-the-spear institution, the Department of Homeland Security's National Bioforensics Analysis and Countermeasures Center, due to be cut, was only restored at the last minute in September.
The persistent problem, though, is that there are any numbers of overlapping, often competing agencies with the will, if not always the means, to deal with any biowarfare crisis. Eight of them are grouped under the National Interagency Confederation for Biological Research, including units of the departments of Defense and Health and Human Services.
As Congress' General Accountability Office put it in October: "The knowledge gaps deemed most critical include data about biological agents that have a high impact on consequence estimates and also a high degree of uncertainty."
It concluded: "Biological threats come from a variety of sources and can pose a catastrophic danger to public health, animal and plant health, and national security."
A Blue Ribbon Study Panel on Biodefense, led by former Sens. Joseph Lieberman and Tom Daschle, former Pennsylvania Gov. Tom Ridge and former Secretary of Health and Human Services Donna Shalala, among others, made a series of 33 recommendations two years ago to secure the United States against a bioweapon attack.
Most have seen only a gesture of implementation. Two years later, Dr. Gerald W. Parker, Jr., director of Texas A&M University's Pandemic and Biosecurity Policy Program, told this same panel: "I am more concerned than ever about the risk of biological threats -- whether from outbreaks, accidents or attacks -- and the need to underpin no-regret attribution decisions with a sound scientific foundation in microbial forensics."
Indeed, bioweapon attacks on the United States can come from any number of sources beyond North Korea -- Iran, Syria or some rogue terrorist group that manages to get a hand on the expertise to deliver a biological blow beyond imagination.
Bioweapons pose a threat that is real and tangible from any number of sources -- and easily as lethal, potentially far broader and as irreversible as the outcome of any nuclear attack by a determined enemy. For the United States to counter effectively will require an exercise in global statesmanship and bureaucratic coordination that must begin today.